Smith, Emil

Emil Smith was born on July 5, 1911 in New York into a family of immigrants. My father was from Ukraine , and initially worked as a tailor at . Later, he managed to open a small store and thereby ensure a decent life for his family. Emil's mother was born in Belarus and was a housewife. The Smiths had two children: Emil and Bernard, who was born in 1907. Parents had no education, but in every possible way encouraged the interest of children in science and art. Thanks to this, Bernard became a respected book editor, producer and writer, and Emil became a scientist and teacher.

Emil's talents showed themselves early. At the age of nine, under the influence of a neighbor who was a radio engineer, Smith began to collect small radio sets that he and his friend sold to relatives and friends. After externally graduating from New York Public School, he entered the at the age of 16.

Entering Columbia University, Emil fell under the influence of two gifted teachers: James Howard McGregor, who taught an advanced course in evolution and genetics, and John Morris Nelson, who lectured in organic chemistry and was actively interested in enzymes. These two professors and instilled in Emil interest in the study of proteins - in the area where the threads of biology and organic chemistry are closely intertwined.

After receiving a bachelor's degree in 1931, Emil continued his studies at the Faculty of Zoology at Columbia University . The country was in the midst of the Great Depression , so Emil, in order to provide for himself, was forced to teach 12 hours a week while doing research.

In his first year of graduate studies, Smith attended a course of sensory physiology Selig Hecht, who was the founder of research in the field of general physiology and physiology of vision ^[3] . Emil chose Hecht as a mentor. Their joint work led to several publications ^[4] .

In his doctoral work, Emil studied the dependence of photosynthesis on light intensity and carbon dioxide concentration ^{[5] [6]} . The results led him to conclude that photosynthesis in green plants is a complex mechanism involving more than one photochemical reaction, an idea that is at odds with the generally accepted work of Otto Warburg .

Smith noted that his mathematical formulation of limiting the rate of photosynthesis can be used as a criterion to justify any theoretical description of the process of photosynthesis ^[5] . This formulation really stood the test of time. In 2009, it remained the best empirical formulation for the model , which is confirmed by comparison with experimental data on ^[7] .

After defending his dissertation, Emil became seriously interested in protein chemistry. During his stay in Colombia, he conducted a study of chlorophyll in green leaves in order to determine its structure. This work was the logical consequence of his dissertation on photosynthesis and a prerequisite for subsequent work on proteins.

Hecht’s laboratory used a method of solubilizing natural rhodopsin by extracting the retina with an aqueous solution containing the digitonin detergent . When Emil applied this method to crushed leaves, chlorophyll was solubilized, and the spectrum of the solution was very similar to the spectrum of intact leaves, but shifted to the longer wavelength region compared with solutions of mixtures of a and b of chlorophyll in an organic solvent. Examination of the extract in an ultracentrifuge showed that chlorophyll was precipitated by particles having a molecular weight exceeding 70,000. This led to the conclusion that "... classical studies of chlorophylls and carotenoids were associated with prosthetic groups of extremely complex specific catalysts, possibly similar to hemoglobin ..." ^[8] . This fundamental contribution has been ignored for almost fifty years ^[9] .

On the recommendation of Hecht, Emil applied for the Guggenheim Fellowship and received it for a trip to Cambridge , where he arrived in September 1938.

Towards the end of the 1930s, Cambridge University was one of the leading researchers in the study of the structure and properties of proteins, and David Cailin’s laboratory at the Molten Institute is particularly attractive in this regard. In an interview with Kailin, Smith expressed interest in the solubilization of cytochrome oxidase with solutions containing bile salts, to an approach that was recognized as successful in preparing rhodopsin. But Cailin recommended continuing research on the chlorophyll-protein complex. This work was suddenly interrupted in September 1939 due to the outbreak of World War II , at which time Smith was forced to return to New York.

Hecht took Emil back to his laboratory in Colombia. There Emil had access to a spectrophotometer and other equipment necessary to complete his studies of the chlorophyll-protein complex and a detailed description of the results.

In studying this complex, he collaborated with Edward Pickels , who, together with Jesse Beams, was the developer of advanced pneumatic models of high-speed analytical ultracentrifuges . They evaluated from the sedimentation constant, the molecular weight of the chlorophyll-protein complex, which was approximately 265,000 ^[10] . These studies have demonstrated that, in the corresponding detergents, the proteins of the photosynthetic apparatus can be solubilized, that chlorophyll and carotenoids remain protein-bound, and that the spectroscopic properties of the chlorophyll complex in the visible region correspond to those measured in vivo for green leaves.

In 1940, Emil moved to New Haven to work at the with Hubert B. Vickery , an energetic and talented chief biochemist at the station ^[11], for the remainder of the Guggenheim scholarship for the second year. Here he gained experience in methods of protein isolation, in the quantitative analysis of nitrogen and sulfur, as well as in the gravimetric analysis of certain amino acids.

Emil participated in the study of hemp seed globulin , which, as shown, can serve as a source of protein for animal diets and act as a substitute for edestin . However, the Marijuana Act of 1937 established restrictions on its distribution and thereby interrupted the research. Nevertheless, Emil succeeded in identifying an easily accessible substitution with a very similar amino acid composition — globulin from pumpkin seeds ( Cucurbita pepo ) ^[12] .

The deadlines for the Guggenheim scholarship came to an end in the fall of 1940, and then there was little work at the university. Thanks to the support of his classmate and close friend at Columbia University, , who worked with at the Rockefeller Institute for several years, Emil continued his work in protein chemistry and enzyme medicine at the Bergmann laboratory. Max, who was the last student of Emil Fisher , was considered the most outstanding researcher in the field of protein chemistry in the world, attracted exclusively gifted scientists to work in the laboratory. Emil’s contemporaries in the Bergmann group were William Stein , Stanford Moore , , Klaus Hoffman and , who became his friends for the rest of his life. He spent two years at the Rockefeller Institute, determining the direction for future research.

Studying the stereospecificity of reactions catalyzed by a proteolytic enzyme ( protease ) of the corresponding protein substrates, Bergmann concluded that recognition of a chiral carbon by an enzyme requires that at least 3 groups surrounding the carbon atom interact with the enzyme ^[13] . This theory has been called the "theory of polyfamily." Evidence that primary intestinal erestin hydrolyzes both L-leucyl-glycine and D-leucyl-glycine has cast doubt on the theory of polysynthesis. Bergmann asked Emil to conduct separate denaturations to show that the activity of intestinal erestin was due to various enzymes. Emil decided to use his own experience in protein purification along with methods. developed in Cailin’s laboratory to isolate fractions that were only active with respect to the L and D isomers , and thereby provide evidence that various enzymes cause the cleavage of two peptide stereoisomers. Emil was also able to show that the activity of purified L-leucine aminoexopeptidase depends on the presence of manganese and magnesium ions ^{[14] [15]} .

Emil was immersed in peptide research when World War II again intervened. Within a few days after the Japanese attack on Pearl Harbor on December 7, 1941, the United States declared war on Japan , Germany and Italy . To contribute to national defense, Bergmann focused his research on synthetic, analytical, and inorganic problems related to chemical poisons, especially nitrogen mustards .

Emil was not ready for a new direction in Bergmann's research. However, a request from the pharmaceutical company ER Squibb & Sons offered Emil the opportunity to make an important contribution to the country's defense. Squibb provided the United States with blood fractions. The Navy and the Marine Corps offered to hire him as a biophysicist-biochemist in a blood fractionation program. Emil accepted the offer and at the end of June 1942 he moved to New Jersey , to the city of New Brunswick .

Joining Squibb, Emil ran into big problems. He had no previous experience in industry, personnel management, which was poorly prepared for the production of high-purity biological products. And the production had to be launched in a short time. So he described the situation in an interview ^[16] :

All these obstacles were soon overcome, and the group began to produce ampoules with sterile solutions of serum albumin on a large scale, and then over time and gamma globulin , fibrinogen , prothrombin , etc. Emil was fortunate to work under the leadership of Tillman D. Gallow , who was an excellent scientist and teacher, with over 10 years of experience at Squibb. The department worked with a wide range of therapeutic drugs from antidotes to insulin . Emil and Gallow collaborated on the characterization of the proteins responsible for the antitoxic activity of horse hyperimmune plasma ^[17] .

In the period from 1942 to 1946, while working at Squibb, Emil also managed to complete a significant amount of basic research, which was included in 8 publications in the Journal of Biological Chemistry for 1946-1947. Emil left Squibb in 1946, but the company retained him as general consultant for the next 20 years.

When the war ended, he sought to return to academia to share his ideas with close friends.

In 1942, a 4-year-old medical school was established at the University of Utah . Maxwell M. Winthrob, an outstanding hematologist, was appointed dean of the faculty of medicine in 1943 with the tasks of recruiting students and developing a research program.

The Public Health Service Act, which was passed on July 1, 1944, authorized the Minister of Health to provide grants to help universities, hospitals, laboratories, and other public or private institutions. Winthrob applied to the US National Institute of Health (NIH) for a grant to support a program to study muscular dystrophy , inherited and other metabolic disorders . Many families in Utah were affected by hereditary muscular dystrophy, and the sheer amount of Mormon genealogy data was a valuable asset for the proposed study. The application has been approved.

In the spring of 1946, Louis Goodman invited Emil to consider participating in a new project. Winrob as the lead researcher led the NIH grant with Horace Davenport ( physiology ), Leo Samuels ( biochemistry ), and Goodman as co-directors. Emil was offered the position of Assistant Professor of Biochemistry and Senior Researcher of Medicine at the University of Utah on the condition that he organize the work of the laboratory for his research, but his equipment will also be available to other researchers in protein chemistry at the university. After meeting with this group, Emil accepted the offer without a preliminary visit to Utah ^[18] .

Emil, Esther, and their two-year-old son arrived in Salt Lake City in July 1946. Upon arrival, Emil set about creating a laboratory and lecturing for medical students and a course in protein chemistry for graduate students. Emil's assistant at Squibb, Douglas Brown, joined him in January 1947 and helped create a new laboratory. Brown, who was an expert in using the new Pickkel ultracentrifuge and Tiselius apparatus for electrophoresis , made a significant contribution to the research, co-author of many works over the years. Their cooperation and friendship continued until 1979, when Emil retired.

In Utah, Emil's attention was drawn to the continuation of the study of proteolytic enzymes, which he began during his work with Bergmann, with particular attention to metal ions, which are necessary for stability and activity. The work from 1947 to 1953 led to several publications on the distribution in tissues, purification, description and substrate specificity of numerous proteolytic enzymes from various organisms.

In 1949, Emil suggested that the metal ion is part of the catalytic center of metalloproteins , and that it plays a key role in the binding of the substrate and hydrolysis through the formation of a chelate complex with the enzyme and substrate ^[19] . This article drew attention to the structural and mechanical aspects of enzymatic catalysis and aroused great interest. However, at that time there was nothing known about three-dimensional protein structures and the nuances of enzymatic catalysis. In his article, Emil warned that the real theory may not be true, and this caution turned out to be appropriate. He later succinctly noted ^[20] :

In the early 1950s, Emil realized that the determination of the sequence of amino acids in proteolytic enzymes is an important step in elucidating their catalytic activity at the molecular level. The time has come when this became possible. In 1948, Sanger completed the determination of the amino acid sequence in two chains of insulin in lengths of 21 and 30 units, respectively.

At the Rockefeller Institute, Moore and Stein developed sensitive methods for the quantitative analysis of amino acids and methods for the separation of proteins using ion-exchange chromatography . They also developed automated fraction collectors and an amino acid analyzer, which were used to determine the amino acid sequence of ribonuclease , a single chain protein with 124 amino acid residues and four disulfide bonds. However, even with such great successes in the methodology, it was not possible to completely determine the primary structure of ribonuclease until 1963.

Emil's attention was focused on papain , a sulfhydryl protease , in which he wanted to determine the amino acid sequence. Starting to work with high-quality dried papaya latex, he developed an elegant method for preparing large amounts of crystalline papain and investigated the substrate specificity of pure protein ^[21] . The papain sedimentation coefficient predicted a molecular weight of 20,500 and a polypeptide length of 170 fragments, which was 36 amino acid residues longer than the ribonuclease chain. Unfortunately, difficulties arose in the process of determining the amino acid sequence in papain, as a result of which the work was completed only in 1970.

The creation of a metabolic laboratory equipped with modern equipment for the purification, description and automatic amino acid analysis of proteins, as well as their separation, along with an increase in experience in determining amino acid sequences, allowed for studies that had interesting results. In 1959, Emanuel Margoliash arrived at the laboratory, who, with the support of Emil, proceeded to determine the amino acid sequence in cytochrome c obtained from a horse’s heart and containing 104 fragments. Over a year of work, he almost completely completed the sequencing of most chymotrypsin peptides.

At this time, Emil learned from that he, together with Gunther Crail, was working in Vienna on tryptic peptides of cytochrome c . This led to collaboration between scientists and the joint publication of results with a fully defined amino acid sequence ^[22] . Since cytochrome c is ubiquitous in eukaryotic cells, knowledge of its amino acid sequences for a wide range of biological species would allow a comparison between phylogenetic trees , which are directly related to the sequence of units and the characteristics of the body. To this end, Emil and Emanuel proceeded to sequencing other varieties of cytochrome c.

Between 1961 and 1970, the Emil and Margoliash groups determined the amino acid sequences of cytochrome c for humans, monkeys, dogs, sheep, whales, sharks, rattlesnakes, dense neurospores ( Neurospora crassa ), wheat germ, etc. ^[23] The data were in accordance with the idea of ​​the amino acid composition of proteins corresponding to species belonging to independent phylogenetic trees and independently evolving. And the determination of the sequence of hemoglobin units, made in 1965 by and Pauling , allowed us to introduce the concept of molecular clocks .

In 1963, Emil left Utah to become dean of the Department of Physiological Chemistry at the . These were the first days of the School. Classes for the first twenty-eight medical students began in 1951. And in the existing buildings of the school and University Hospital in 1954 and 1955, respectively. Shortly after arriving in Los Angeles, Emil renamed the faculty name to the Department of Biological Chemistry and began to make efforts to make it a strong and promising educational institution by attracting talented young scientists.

In early 1965, Emil, together with Paul Boiler, established the Institute of Molecular Biology at the University of California, Los Angeles.

At the university, Emil continued the research projects launched in Utah. The remainder of his career, he devoted to the determination of amino acid sequences in carefully selected proteins. Initially, emphasis was placed on cytochrome c isolated from various types of eukaryotes. The results of these studies together allowed a look at the evolution of proteins.

In parallel, Emil launched a project to determine amino acid sequences in BPN 'and Carlsberg subtilisins , secreted proteolytic enzymes of hay bacillus ( Bacillus subtilis ), a variant of amylosacchariticus , and in Bacillus licheniformis . These enzymes, which are serine proteases, become inactive upon reaction with diisopropyl fluorophosphate, as do the trypsin family proteases. Data on amino acid sequences along with later defined crystal structures led to unexpected results. Even though the catalytic activities and specificities of these enzymes were very similar, these two highly homologous proteins differed from each other in 82 (30%) of the 275 positions. The three-dimensional structures of the two subtilisins were surprisingly similar, but had no similarity with the proteases of the family trypsin. It was unexpectedly discovered that the active centers of subtilisins and proteases of the trypsin family had “catalytic triads” of fragments of aspartate, histidine and serine, the general mechanism of catalysis, as well as the nature and the same arrangement of binding sites with the polypeptide substrate. This remains a striking example of convergent evolution at the molecular level.

In 1967, James Bonner suggested that Smith collaborate in determining the sequence of amino acid residues in histone IV from the thymus and from the kidneys of pea seedlings. Earlier, Douglas Fambro showed in his laboratory that histone III – IV data obtained by polyacrylamide gel electrophoresis are very similar in amino acid composition and have identical N-terminal groups ^[24] . Emil accepted the offer, and Bob Delange , a talented employee specializing in protein chemistry, set to work. Intensive work was underway on the project, and already in 1969 the complete amino acid sequences of two histones were published. The results were impressive. In the sequences, 100 residues from 102 were identical with two substitutions of valine / isoleucine and lysine / arginine . These are the most similar protein chains known to organisms that are so diverse. It is noteworthy that there were differences in the structure of the post-translational modification in the size and distribution of ε-N-acetyllysine.

However, an even more complex picture of post-translational modification was observed for calf histone III calf thymus. When ε-N-methylation of lysine units, ε-N-monomethyl-, ε-N-dimethyl-, ε-N-trimethyllysine were observed at each active center and much less frequently in other positions ^[25] .

Emil showed great efforts to promote international scientific cooperation, in particular, with the USSR and China. In 1973, as co-chair of the Committee on Scientific Relations with the People's Republic of China, he led a delegation for negotiations in Beijing for the first exchange agreement between the National Academies of Sciences of the United States and China, reaching the end of a long period of time when there were no contacts between scientists of the two countries. During these negotiations, he met with Prime Minister Zhou Enlai .

In 1954, Smith published the textbook Principles of Biochemistry, co-authored by Abraham White , Philippe Handler, and Stefan de Witt . For 22 years, the book has withstood 7 editions.

In the middle of school time, Emil started playing the saxophone and after two years of training with the teacher, he started working as a professional jazz musician, thanks in part to the Moss Hallett Agency . The income from the performances allowed to pay for college at Columbia. During his last club performance on December 31, 1931, he was part of the Dixieland band Eddie Edwards , playing in in New York. The next day, Emil met his future wife, Esther Press, at a New Year's party.

In one of his speeches, Emil thanked his wife for the many decades of support that he received from Esther:

He was very proud of his sons, Donald and Jeffrey, and was particularly pleased that both had chosen a scientific career, one in biochemistry, the other in medicine ^[16] .