AN INTERVIEW WITH MANUEL VARELA AND ANN VARELA: From Brooklyn came the Brooklyn Dodgers and Arthur Kornberg

May 24, 2020 by

Arthur Kornberg

Michael F. Shaughnessy –

1) So many extraordinary talents came from Brooklyn—but one scientist stands out—Arthur Kornberg—When exactly was he born—do we know what part of Brooklyn exactly, and where did he go to school?

Dr. Arthur Kornberg, 1959 Nobel Laureate in chemistry, is widely recognized for his discovery of the enzyme DNA polymerase, a protein that makes the life-coding DNA molecule.

Kornberg was born amid the great influenza pandemic on the third of March 1918, in the U.S., New York City, in the lower east side of the Brooklyn borough, a district known then as the Bath Beach section. His parents, Joseph and Lena Kornberg (who emigrated from Poland—formerly Austrian Galicia), were Jewish. For almost 30 years, Joseph was a sewing machine operator in a New York sweatshop. They owned and operated a small hardware and home furnishings store after Joseph’s health began to decline.

Kornberg was brought up in a middle-class household. He collected matchbook covers from the Brooklyn streets. He related that he had no exposure to the sciences as a child. Nevertheless, Arthur Kornberg skipped grades several times in primary school due to his intellect. He attended Abraham Lincoln High School, and he graduated from high school at the age of 15.

During the same year, 1933, he entered City College of New York, and in 1937, Kornberg received his B.Sc. from the University of Rochester. In 1941, Kornberg graduated from the University of Rochester with an M.D. degree. Between 1941 and 1942, Dr. Kornberg received internship training at Strong Memorial Hospital in Rochester, New York.

2) The military played a small role in his life—what happened?

In 1942, during World War II, he fulfilled military service as a ship’s doctor on a U.S. Coast Guard vessel in the Caribbean. He had held the rank of lieutenant.

After earning his medical degree, his entry into this type of military service was circuitous. Because his family was Jewish, Dr. Kornberg was passed over for several medical fellowships of his first choice, namely pathology. He was passed over in virtually every other medical field except in the study of liver function, in which he had studied bilirubin levels in jaundice patients. While stationed aboard a Navy vessel during the Second World War, Kornberg continued his work with bilirubin levels in the ship’s sickbay.

It had not been a pleasant experience. Kornberg repeatedly clashed with the ship’s captain, who was not impressed with Kornberg’s lack of military discipline or his indifference to the hierarchy of his captain’s military rank. They consistently argued, with his captain asserting that he was, after all, the captain, to which Lt. Kornberg would reply that he was, well, the ship’s doctor.

Kornberg relayed one positive incident during his military service many years later. It occurred during a stayover while the ship was docked in St. Petersburg, Florida. Kornberg met a physician who was a surgical specialist of the ear, nose, and throat, and the surgeon offered to teach Kornberg how to perform a tonsillectomy. After recruiting a ship’s crewmember with a sore throat and an enlarged set of tonsils, the surgeon demonstrated the procedure on the patient’s left tonsil by injecting it with anesthetic, ligating it with a wire loop, and pushing the syringe’s plunger, readily popping out the inflamed tonsil without any trouble.

The right-side tonsil was now Kornberg’s. As shown, he injected the tonsil with the anesthetic but had incorrectly pushed the needle through the tonsil. Thus, not knowing the tonsil was not anesthetized, he duly went through the entirety of the procedure as he had just been taught. However, as he pushed the syringe plunger, popping out the tonsil, the young sailor jumped out of his chair and let out an ear-piercing cry of extreme pain!

The next day, Kornberg tried but could not avoid meeting face-to-face with his tonsillectomy patient. To his great surprise, the young sailor had informed him that the side Kornberg had operated on felt great with no pain whatsoever. Unfortunately, the sailor told him that the left side, of which Kornberg’s surgical instructor had demonstrated the tonsillectomy, had turned extremely painful, referring to Kornberg’s surgeon colleague as a “butcher!”

After his war service had ended in 1942, Kornberg directed research on enzymes and intermediary metabolism in the Nutrition Laboratory at the U.S. National Institutes of Health (NIH), Bethesda, Maryland, until 1959. In 1945, Kornberg took a one-year leave of absence from the NIH. He engaged in studies of the metabolic enzymes involved in adenosine triphosphate (ATP) production at New York University. In 1953, he was appointed professor and director of the Microbiology Department at Washington University School of Medicine, St. Louis, Missouri, where Kornberg studied how living organisms manufacture nucleotides. In 1959, Kornberg became professor, and first chairperson, of biochemistry at Stanford University, Palo Alto, California, where he remained for the extent of his life, active in research until his death in October of 2007.

3) Bilirubin and jaundice—were significant in the life of Kornberg, as he had what we know now as Gilbert’s Disease. How did this influence him from the very beginning of his career?

Because Kornberg had the expertise of sorts with the liver and bilirubin, his military service (to the delight of his ship’s captain) was cut short, and Kornberg was transferred to the NIH at Bethesda, Maryland, in the U.S.

Kornberg’s foray into the physiology of jaundice and its involvement with bilirubin came about because he had the so-called “medical student syndrome.” The “ailment” arises out of the notion that medical students, new to the various signs and symptoms of the diseases they study, somehow recognize these same indicators in themselves. Consequently, many medical students are prone to believing they have the medical conditions they learn in school.

In the case of Kornberg, he was quite susceptible to the syndrome, at first. For instance, he mistakenly thought he had dreaded cases of amyotrophic lateral sclerosis, an aortic aneurysm, tuberculosis, and leukemia! He had misdiagnosed himself based on their associated symptomology.

Kornberg cannot be blamed too vigorously. It was known that one of his medical school faculty, Professor George H. Whipple, routinely encouraged his students to take deep whiffs of dissected lung tissue from corpses who died of tuberculosis. The teaching technique was meant for the students to gain a better understanding of the dread consumption. Unfortunately, the T.B. cadaver lung smelling practice often resulted in the medical students contracting the contagion!

While Kornberg did not contract T.B., he was not entirely mistaken in one of his diagnoses, either, as he surely did have a case of infectious hepatitis! He had exhibited jaundiced eyes (the whites of his eyes had been mildly yellow), and a physiologically based laboratory confirmation was attained. The blood tests conducted by Kornberg involved the measurement of bilirubin, and his levels in the blood were quite elevated. He indeed officially had the so-called catarrhal jaundice, as infectious hepatitis was called in Kornberg’s day. Frequently, an overabundant level of bilirubin is a complication of infectious hepatitis in patients who, for any of a variety of causes, cannot process the biochemical. A genetic disease is one such reason, and Kornberg had it.

Kornberg had followed up on his blood findings by measuring bilirubin in samples provided by his medical student colleagues, some of whom also had jaundice and compared them with others who did not. He also compared his findings with clinical hospital records, examining the lab test results of hepatitis patients and healthy individuals.

Bilirubin is a reddish-orange or yellow substance that is produced in the liver as a result of the degradation of old red blood cells. Sometimes these colorations manifest themselves in healing bruises on a skin injury. The biochemical called heme that resides within red blood cells is degraded in the liver. One of the intermediates of heme degradation is biliverdin, which goes quickly to the bilirubin. Next, bilirubin is sent to the bile, and it is converted to urobilinogen by enzymes made by bacteria in the large intestine of humans. Some of the urobilinogen is taken back into the blood where it goes to the kidney and is excreted in the urine, giving it its typical yellow color.

Kornberg then conducted an experiment in which he injected bilirubin into volunteer medical students and assessed how quickly they could eliminate the compound from their blood and into the urine. The results formed the basis for his first publication in a scientific journal, in 1942.

As hinted to above, Kornberg had discovered early on that the jaundice condition was not necessarily due to infectious hepatitis per se but instead because of an inborn error of metabolism, called Gilbert syndrome. Professor Augustin Nicolas Gilbert had initially described this ailment in 1901. It is a rare genetic disease characterized by a defective protein called UDP-glucuronosyltransferase, polypeptide A1. Gilbert disease patients cannot adequately participate in the heme degradation process, and it stops at bilirubin.

Interestingly, premature and newborn infants occasionally lack the enzyme that degrades bilirubin, and they acquire the jaundice appearance due to the abnormal bilirubin accumulation. Such infant patients are then often placed inside an incubator that is outfitted with a fluorescent lamp (a “bili-light”). The light activation then facilitates the photochemical conversion of bilirubin into products that the infant can more readily excrete. The bili-lights are used even in modern times.

4) Kornberg’s mother died of spores because of a routine gall bladder procedure—and this resulted in Kornberg’s research shifting to endospores. How did his research in that area fare?

In 1939, when Kornberg was 21 years old, his mother was tragically stricken with the dreadful gas gangrene because of post-operative infection. The bacterium that killed his mother is called Clostridium perfringens, and it produces endospores.

These endospore structures are benign, environmentally stable entities that can withstand harsh conditions, like heat, chemicals, radiation, and a lack of water. When the environmental conditions improve, the dormant endospores can then germinate. The germination process produces vegetative (metabolizing) bacterial cells, which grow quite readily. If conditions become less than optimal, then the living bacterial cells undergo sporulation to form endospores.

Such bacterial structures are found in many soil types. If a person suffers a trauma in which the skin is broken, the injury might be exposed to endospores from contaminated soil or other sources. The invading bacterial endospores can germinate into toxin-making vegetative cells. These metabolizing cells then synthesize foul-smelling organic molecules and gases, killing tissue along the way.

The wounds that permit endospore entry can be as minor as a scratch, or a pinprick, or perhaps trauma wounds from automobile accidents, or acts of violence such as knife or gunfire wounds. Typically, a patient suffering from the gas gangrene can quickly succumb to the affliction and die unless debridement or even amputations are swiftly performed. Occasionally the amputations can be drastic, and the patient tragically dies anyway. The gas gangrene used to so dangerous that more deaths were due to it during the American Civil War than those due to immediate wounds from gunshots or shrapnel.

Kornberg never forgot the plight of his mother and her encounter with the lethal endospores. During his Nobel Prize-winning research work that he spent discovering the DNA polymerase, he was also actively pursuing research investigations into the endospores. This phase of his endospore work took the greater part of the 1960s and resulted in the publication of over two dozen papers.

His efforts into endospore research on how these hardy entities could be destroyed prove helpful during the food canning process for preservation purposes. Alternatively, the endospores’ work could be exploited to kill pests that infested crops.

One of their breakthroughs involved the discovery that a typical endospore structure contained all the genetic information necessary to initiate the production of a viable new bacterium. Furthermore, Kornberg’s laboratory discovered that the endospores harbored all of the essential biological machinery for germination to a full-fledged bacterial cell. These two facts flew in the face of the then widely accepted notion that endospores merely harbored fuels in reserve for germination, rather than harboring the genetic and biochemical machinery, as Kornberg had correctly discovered. Soon, however, the endospore fuel reserve theory had collapsed as the result of Kornberg’s new findings.

Unfortunately, Kornberg abandoned the endospore investigations. Two main reasons account for leaving this research behind. The first was that one-by-one, his postdocs kept switching from the endospore study to the more exciting DNA polymerase project. The enzyme was, after all, responsible for synthesizing DNA, the molecule of life! The glamourous nature of molecular biology and its famous DNA molecule proved to be too tempting to resist.

The second reason was that endospores involved complicated steps. The process of endospore formation is called sporulation. Germination consists of the conversion to vegetative forms. Each step in these two processes was tied to specific biochemical players and physiological behaviors! To this day, the investigative work dealing with endospores is still an actively ongoing field of science. Nevertheless, despite the critical nature of the endospore field, and their dastardly involvement in killing his mother, Kornberg had held an undeniable fascination with and profound respect for the endospore-forming bacteria, titling a biographical chapter devoted to the topic as “Bless the Little Beasties.”

5) In 1959 he was able to isolate the first DNA enzyme (which is currently known as DNA polymerase), and he later won the Nobel Prize for this. What exactly did he find that was of significance?

In 1954, Dr. Kornberg started his Nobel Prize-worthy project on the synthesis of DNA and his consequent discovery of the now very famous DNA polymerase enzyme that is responsible for making the equally famed DNA.

At the time, he had amassed a collection of enzymes that he had purified and studied in biochemical detail. He had already been interested in the study of enzymes for more than ten years. A natural progression had emerged from his interest in nucleotide biosynthesis using vitamins as co-factors to the use of the nucleotides for DNA biosynthesis.

Incidentally, he also had an interest in the biosynthesis of RNA. Still, we will discuss what happened, below, when we address his work with Dr. Severo Ochoa, who would share the Nobel Prize with Kornberg.

To investigate DNA polymerase, the molecule that would result in the Nobel, the Kornberg laboratory switched from animals and yeasts to using bacteria. The now-famous Escherichia coli was the bacterium of choice for their experiments. Their approach would involve exploding the bacteria and reconstituting the cytoplasmic machinery by adding back all the individual necessary microbial components required to make DNA. The cell lysis method that was employed produced a so-called cell-free extract, consisting of the intracellular microbial machinery.

First, Kornberg added radioactive thymidine, which is one of the four nucleotides that make up DNA molecules to the cell-free Escherichia coli extracts. Next, he measured the amount of the radiolabeled thymidine incorporated into a growing DNA molecule. The results were disappointing, as very little of the radioactive thymidine was found in any of the DNA. Instead, they learned that the labeled thymidine ended up in some sort of phosphorylated DNA precursor, that is, within the nucleotide building blocks. They made the most of this initially disappointing finding. They hypothesized that the phosphorylated nucleotides were precursors for the biosynthetic production of DNA.

Just as they were preparing to follow up on this idea, the Kornberg laboratory then learned from a visiting scholar, Dr. Herman Kalckar, that Ochoa had discovered RNA production from an enzyme! It was stunning news. Furthermore, they learned from Kalckar that the process involved a phosphorylation event! The Ochoa laboratory had found that their phosphates went to ADP and then to RNA.

Thus, Kornberg and his laboratory assistants repeated the radioactive thymidine incorporation experiments with Escherichia coli, and this time they added ADP instead of ATP to make the DNA synthesis reaction proceed to higher levels. The minor experimental modification with ADP seemed to work! They observed a spike in the synthesis of DNA as measured by the radioactive thymidine insertion into newly made DNA and experimental confirmation of DNA production by its detection with the DNase treatment.

They repeated the experiment. This time Kornberg added fully phosphorylated thymidine to the reaction; the biochemical harbored three phosphates. Then, they measured the radioactive thymidine triphosphate (TTP) incorporation into newly made DNA. Lastly, they detected the new DNA by its susceptibility to DNase degradation. This time, they observed massive levels in DNA making activity!

With an improved capability to detect DNA making activity, Kornberg was able to exploit the straightforward detection method to proceed with the purification of the enzyme responsible for DNA synthesis. Each step in the enzyme isolation process could be evaluated for its activity along the way, making it readily possible to purify the DNA polymerase enzyme, as it would come to be known. The DNA polymerase work from the Kornberg lab was published with Uri Littauer (post-doctoral fellow), Robert (Bob) Lehman (postdoc fellow), Maurice Bessman (postdoc), and Ernie Simms (lab assistant), in two keynote papers, in 1956 and 1957.

6) He used to work with rats (as I did), but Kornberg fed them to investigate vitamins—but he then moved on to enzymes—why is this important?

During World War II, in 1942, Kornberg joined forces with the vitamin hunters. He had been inspired by the works of Dr. Joseph Goldberger, who had studied disease epidemics that were brought about by vitamin deficiencies, and by Dr. W. Henry Sebrell, who was laboratory chief of the Nutrition Lab at the NIH and immediate supervisor to Kornberg. At the time, Kornberg had just completed military duty. Goldberger had discovered that pellagra, a condition characterized by a lack of vitamin B3 (i.e., nicotinic acid or niacin), could be alleviated by improvements in dietary practices.

Kornberg’s first project dealt with determining why laboratory rats suffered from a terrible blood disorder. It was a type of anemia called granulocytopenia that manifested itself when the animals were fed an artificial diet containing a sulfa drug such as sulfanilamide, sulfadiazine, or sulfathiazole. He found that the anemic rats could be much improved with a dietary supplement consisting of yeast extract or liver.

After publishing the work in Science, in 1943, Kornberg zeroed in on folic acid, which they then demonstrated had been the missing essential ingredient. Seemingly, the sulfonamides prevented the production of folic acid by blocking the biosynthesis of a critical metabolite called para-aminobenzoic acid (PABA), and it stopped the laboratory rats from producing enough red blood cell constituents from the folic acid.

Next, Kornberg turned his attention to vitamin K. At the time, it was understood that individual bacteria in the human gut played a role in supplying specific needed vitamins, such as vitamin K. A mystery had arisen. Kornberg read a report that found PABA prohibited the sulfa drugs from provoking the rat anemia from an artificially induced vitamin K deficiency. That is, a vitamin K deficiency could not be caused by PABA treatments. It was a mystery because gut bacteria which were known to supply vitamin K, and PABA was known to prevent folic acid production and thereby prevent vitamin K in these bacteria. Thus, the observation that PABA stopped sulfa drug induction of a vitamin K deficiency pointed to the target site for the sulfa drugs occurring elsewhere in the rat.

That was the mystery: where within the rat body did the sulfa drugs work? Kornberg’s next experiment found the target site: it was the large intestine. Somehow, the PABA found its way via the blood to enter the large intestine in amounts sufficient to counteract the inhibitory effects of the dietary sulfa drugs. It was a significant finding, and it was published in the prestigious Journal of Biological Chemistry, in 1944.

Kornberg converted from the study of vitamins to enzymes in 1945. In an autobiography, he proudly stated that he joined the enzyme hunters. Kornberg moved to the Medical School of New York University to study under the famous Severo Ochoa. He started his enzymology studies with aconitase, an enzyme that participates in the Krebs cycle. Unfortunately, he had failed to demonstrate its isolation from the muscles of the heart tissue definitively. Interestingly, despite this failure, he was permanently hooked on the enzymes.

The second attempt to purify an enzyme turned out to be Kornberg’s first successful endeavor after his conversion to enzymology. He successfully purified the protein he called a malic enzyme, which was known to convert malate into pyruvate. The work was duly reported in the Journal of Biological Chemistry again, in 1947, with Ochoa and his lab mate Alan Mehler. Interestingly, the malic enzyme term is still in use today. The enzyme has relevance to this day in the production of fine Burgundy and Bordeaux wines.

Kornberg was to continue with his paradigm of enzyme studies, namely, measuring their activities by performing enzyme reactions in test tubes while taking successive steps in their isolation. He had learned these methodological philosophies from Severo Ochoa, Gerty Cori, and Carl Cori. All of them inspired Kornberg to jump on the ATP bonanza and study respiration in a test tube!

Using this approach, he went on to purify many new enzymes, like, of course, DNA polymerase. He found nucleotide pyrophosphatase, primase, and helicase, to name a few. He never purified aconitase. That honor went to Christian B. Anfinsen and John M. Buchanan, who first published the partial purification of aconitase.

Kornberg related this new work as an odyssey of a biochemist who was struck with love for enzymes. It was a passion to last a lifetime.

7) Longevity plays a role in many achievements. Kornberg was able to work with many other capable scientists—who were they, and what do we know about them?

Indeed, Arthur Kornberg lived to be an impressive 89 years old. He worked with many prominent scientists of the day, working in their labs for advanced training, or visiting their labs as an established collaborator. At the same time, research luminaries had paid working visits to his lab. I will focus on a few of these investigators who were hugely influential to Kornberg and his research efforts.

No doubt, one of the first notable scientists with whom Kornberg worked with was his post-doctoral mentor, the much-admired Professor Severo Ochoa. You will recall Ochoa, who is featured later in our book series, was to share the 1959 Nobel in physiology or medicine with Kornberg. As Kornberg discovered DNA polymerase, Ochoa discovered the polymerase for RNA synthesis.

Kornberg attributes his love for enzymes directly to Ochoa, later remarking that it was Ochoa’s influence that made the postdoc experience one of the most exhilarating and happiest in his life. In the Ochoa laboratory at the Medical School of New York University, they studied aerobic phosphorylation together, in 1946. Kornberg had attempted to isolate aconitase but was thwarted, as it turned out to be complicated. The enzyme performed two biochemical reactions of the Krebs cycle. First, aconitase catalyzed the interconversion of citrate and isocitrate. Second, the catalyst interconverted cis-aconitate to citrate or isocitrate.

Not to be deterred, Kornberg and Ochoa then tried their acumen in purifying and characterizing the now-famous malic enzyme, publishing their work on their findings with oxidative decarboxylation in pigeon liver extracts. They reported this new work, and it was the first enzyme that Kornberg had ever purified.

In 1948, Kornberg was a visiting scientist in the legendary Cori laboratory, headed by Gerty and Carl Cori, both of whom are featured in our first book together. The Cori wife and husband team were celebrated for having discovered the famous Cori cycle, garnering the 1947 Nobel Prize in the category of physiology or medicine. In the Cori lab, Kornberg studied enzymatic co-factors that play a role in the biosynthesis of the nucleotides. He focused his attention on the enzyme called nucleotide pyrophosphatase. He discovered that ATP served as a co-factor to cleave NADP, making NAD+ and inorganic pyrophosphate in the process.

An astutely fortuitous outcome of Kornberg’s experience in the Cori laboratory was that it prepared him for the pathway to the Nobel. The Cori studies of carbohydrates and glycogen metabolism had invoked the use of a pre-formed polymer of sugars, i.e., a primer, to grow longer chains of carbohydrates while making glycogen enzymatically.

Thus, when Kornberg later conducted his studies of DNA synthesis, he, too, used the Cori method of adding an extract containing short stretches of DNA, a primer, to study the enzymatic activity of DNA synthesis. This minor modification turned out to enhance their radioactive thymidine incorporation significantly during DNA synthesis. He also added DNA to the experimental assay of DNA polymerase because of non-specific nuclease would otherwise wreak havoc with any newly made DNA, and it would have been difficult to proceed with the isolation of the acclaimed DNA polymerase enzyme. Thus, had he not added the short DNA primer into his reaction mixture, he might never have seen a positive Nobel-winning signal for DNA synthesis. Today, we know the natural replication primer is composed of short RNA chains.

Har Gobind Khorana, a remarkable scientist, visited the Kornberg laboratory in the late 1950s and early 1960s. Khorana is well known for having solved the puzzle of the genetic code, sharing the 1968 Nobel Prize in medicine or physiology with Robert Holley and Marshall Nirenberg.

Khorana and Kornberg studied an enzyme called PRPP synthetase. The PRPP is an acronym that stands for 5-phosphoribosyl-1-pyrophosphate, and it serves as an essential intermediate in the synthesis of purine nucleotides. Working together, the two investigators became lifelong friends. They established that ATP was a necessary player in the production of these nucleotides. In later years, Kornberg was to remark that the PRPP synthetase enzyme was one of his favorites.

8) Certain things in life are sometimes absolutely unbelievable. Arthur had a son, Roger, who coincidentally went on to win his own Nobel Prize! How were the two Nobel Prizes linked?

Indeed, Sylvia and Arthur Kornberg were to have three children, Roger David, Thomas Bill, and Kenneth Andrew. Like their father, Roger and Thomas became biochemists, while Kenneth became an architect.

As you know, Roger’s father earned the Nobel for his discoveries regarding the biosynthesis of DNA via its dedicated polymerase. Like his father, Roger Kornberg would also go on to win the Nobel Prize in 2006, this one in the area of chemistry.

Roger’s Nobel had to do with his discoveries on the regulation of eukaryotic transcription. In yeast, Roger Kornberg discovered the so-called Mediator system, which is a complex of proteins that serve to transmit signals, which then regulate RNA polymerase activity. The Mediator turned out to be a finely tuned system in our understanding of transcription.

Roger Kornberg was also an accomplished X-ray crystallographer. Of note, his laboratory determined in fine molecular detail the structure of RNA polymerase! This versatile molecule can perform a variety of activities that its counterpart in DNA polymerase cannot. For example, RNA polymerase has DNA unwinding helicase activities, proofreading abilities, and does not need a primer! While the proofreading accuracy of RNA polymerase does not match the very high accurateness observed for the DNA synthesis machinery, RNA polymerase does not require as much help as DNA polymerase does.

Nevertheless, both polymerase molecules (for RNA and DNA production), were intensely studied by the father and son generations. They are intensively studied by new generations of biochemists and molecular biologists alike today. These two nucleic acid-making systems will no doubt continue to be of significant importance for many more generations to follow, as they are central to the secret of life itself.

9) When Kornberg was awarded the prize—Kornberg’s wife said, “I was robbed.” How much work did Sylvy do, and how much time and work did she contribute to Kornberg’s research?

Indeed, Kornberg’s wife Sylvia (Sylvy) Ruth Levy-Kornberg was an accomplished scientist in her own right. She undertook studies at the University of Rochester in New York, earning an undergraduate degree in biochemistry in 1938 and successfully defending her master’s thesis project to attain her M.S. graduate degree in biochemistry in 1940. Her thesis work was dedicated to the study of lipid metabolism in tumor tissue.

She was known as a gifted scientist. The story is told by Arthur that he once boasted to her about earning a perfect score in chemistry on an N.Y. State Regents test. Levy-Kornberg replied that she, too, had received a perfect score on the exam not only in chemistry but also in geometry and algebra!

Levy-Kornberg worked briefly at the National Cancer Institute in Maryland, where she conducted studies on plant compounds and cancer. Her first publication, in 1946, was based on investigations of a series of quaternary ammonium compounds derived from a group of heterocyclic bases and which were prominent in the chemotherapy of certain cancers.

Levy-Kornberg was a science book editor for a time, working for Academic Press and for Wiley, which was previously Inter-science publishers. Levy-Kornberg also worked in Arthur’s laboratory at the School of Medicine at Washington University, St. Louis, MO, and later at Stanford University, California. She studied the enzymes called polyphosphate synthetase, polyphosphate kinase, and a series of glucosyltransferases.

In particular, she is noted for having studied an enzyme involved in the purine catabolic pathway of GTP. The GTP-degrading protein also played a vital role in the DNA polymerase studies of Arthur and laboratory co-workers. During her work with the GTP metabolism, Arthur was having trouble with individual agents in the extracts that were inhibitory to the activity of his DNA polymerase. She had discovered that her new enzyme was the confounding culprit, as it was degrading the necessary GTP substrate and was not available to participate in DNA synthesis by its polymerase. Thus, she solved an urgent problem and, therefore, facilitated continued advancement in the DNA polymerase effort. Altogether, Levy-Kornberg published about eight papers, according to PubMed.

Soon after it was announced that Arthur had gotten the Nobel, Levy-Kornberg had joked to the news reporters present that she “was robbed!” garnering a roar of laughter in the crowd of reporters and onlookers. Unfortunately, however, the joke soon took another life of its own, being interpreted later as a sincere comment as the story cycled through the various news outlets. On the contrary, she had been genuinely delighted for her husband and had no such reservations about Arthur’s work in the least. It seemed that she had to undertake damage control efforts to straighten out the misunderstanding. Eventually, the difficulty died down. That her joke took a negative turn at all was at first a source of humiliation, and later it became a sort of a fun family affair, as the years went by. Time, it seems, had healed the predicament.

After her retirement, she worked from home editing manuscripts. At some point, she developed amyotrophic lateral sclerosis and eventually became wheelchair-bound. She passed away on the sixth of June, in 1986, at 69 years of age.

10) What have I neglected to ask about this very famous scientist?

During the early 1970s, Kornberg’s DNA polymerase work was in serious trouble and quite vigorously questioned. His beloved second molecule of life had even been referred to as a “red herring” that was merely masquerading as the famous correct DNA replication enzyme.

The trouble with Kornberg’s DNA polymerase started in 1969, with the publication in Nature of the work by Paula de Lucia and John Cairns. They had isolated a mutant of Escherichia coli that was evidently devoid of the Kornberg enzyme but, nevertheless, grew new generations of bacteria to significantly high levels. The mutant Escherichia coli cell became known as the “Cairns mutant.” It was a mystery because if the Cairns mutant lacked DNA polymerase, how could the mutant bacteria grow if it cannot make DNA to do so?

The levels of criticism only grew louder as the numbers of Escherichia coli mutants continued to accumulate. Each mutant was found to be defective in distinctively different genes than that thought to encode Kornberg’s DNA polymerase enzyme. Publication of a popular series of anonymous articles in Nature New Biology harshly criticized the DNA polymerase work of Kornberg. These papers would later be referred to by Kornberg as a vendetta, and it was a clear indication that the discourse deeply affected him.

The outcry got worse as not only was the integrity of the protein had come into serious question, but also the mechanism of the DNA synthesis itself, not to mention the roles of its building blocks, and even the validity of the DNA polymerase assays were questioned. In a scathing series of publications, the vendetta, the thymidine incorporation technique, was believed by many investigators to be a troubling obstacle to the discovery of the so-called “true” DNA polymerase!

Of course, we know in modern times that virtually all these criticisms were for naught. Kornberg had been quite correct in claiming that he had indeed discovered the true DNA polymerase. However, exoneration for Kornberg did not definitively arise until his son Thomas entered the picture.

Thomas Kornberg was gifted at an early age in the field of music, playing the cello at the prestigious Juilliard School for the arts and music in New York. Unluckily, Tom had acquired a hand injury that precluded his pursuit of cello performance, and it ended his career as an aspiring cellist.

Thus, Tom Kornberg became a full-time undergraduate student at Columbia University, where he encountered another vexing problem. In one of his courses in biology, he was privy to disparaging comments that had been floating about regarding his father’s DNA polymerase work, and they, too, affected him deeply.

He then became an assistant in the laboratory of Dr. Malcolm Gefter at Columbia University, and Thomas investigated the Cairns mutant situation, despite not having a great deal of lab experience. Soon, however, Tom Kornberg and Gefter discovered two additional polymerase proteins! Thus, they called his father’s original enzyme DNA polymerase I, and theirs as DNA polymerases II and III. It was a breakthrough of significant proportions, and it provided firm experimental evidence in support of Arthur Kornberg’s original DNA polymerase work! The new evidence was published in a series of articles in 1970 and 1971.

The discoveries by Thomas Kornberg had demonstrated that the mode of DNA replication was a complicated process. New investigations led to the elucidation of additional players for making DNA. Many proteins were involved in DNA synthesis!
Figure DNA Synthesis

The DNA replication mechanisms had similarities in prokaryotes and eukaryotes. The DNA polymerases I (Pol I), II (Pol II), and III (Pol III), of prokaryotes, have their counterparts in eukaryotes. The DNA polymerases of eukaryotic cells are denoted as α, ε, and δ, plus γ, β, ζ, η, and κ.

In Escherichia coli, we know today that the Pol I enzyme plays roles in replication, DNA repair, and DNA recombination. The Pol II polymerase functions in a specialized form of DNA repair, and Pol III polymerase performs the bulk of elongation during DNA synthesis. In the late 1990s, DNA polymerases IV and V were discovered. They are also thought to serve in DNA repair. The DNA polymerase enzymes would connect individual incoming nucleotides to each other forming long DNA chains using the parental DNA sequences as a template. It was an elegant process!

DNA synthesis (replication) has many other players. For example, DNA primase, which synthesizes short, stretches of RNA, serves to help initiate replication. Helicase unwinds the double-stranded DNA to expose the internal nucleotides so that DNA polymerases can gain access to them. The single-stranded binding proteins serve to stabilize the individual separated DNA strands to prevent them from reacquiring a double-stranded form. Topoisomerase, also known in some cases as DNA gyrase, relieves the so-called torsional stress that is induced by helicase.

The two strands of DNA are duplicated in somewhat different fashions. The leading strand synthesis proceeds continuously, while that of the lagging strand occurs dis-continuously. The difference in replication is because, in the lagging strand, the DNA must be unwound first by helicase, forming a replication fork and exposing template nucleotides for DNA polymerase to work. The Okazaki fragments on the lagging DNA strand are the result of this dis-continuous mode of DNA synthesis. The short DNA pieces on the lagging strand were discovered in the laboratory of Dr. Reiji Okazaki, who proposed the dis-continuous nature of DNA synthesis. The DNA ligase enzyme then seals up the lagging strand to complete the two-stranded nature of the DNA double helix.

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