Herman Russell Branson
|Died||June 7, 1995 80)(aged|
|Thesis||I. The effects of soft x-rays on Tubifex Tubifex, II. The construction and operation of an x-ray intensity measuring device, III. The quantization of mass. (1939)|
|Doctoral advisor||Boris Padolsky|
Herman Russell Branson (August 14, 1914 – June 7, 1995) was an American physicist, chemist, best known for his research on the alpha helix protein structure, and was also the president of two colleges.
Branson received his B.S. from Virginia State College in 1936, and his Ph.D. in physics from the University of Cincinnati, under the direction of Boris Podolsky, in 1939. His thesis was in three parts, the first involved the interaction of x-rays with Tubifex tubifex (or sludge worm), the second involving the design and construction of an X-ray intensity measuring device, and the third section on the quantization of mass using the Dirac Equation.After a stint at Dillard University, he joined Howard University in 1941 as an assistant professor of physics and chemistry. As a scientist, Branson made significant contributions to how proteins work, and how they contribute to diseases such as sickle cell anemia. He remained at Howard for 27 years, achieving increasingly important positions, eventually becoming head of the physics department, director of a program in experimental science and mathematics, and working on the Office of Naval Research and Atomic Energy Commission Projects in Physics at Howard University. One of his students would include Marie Maynard Daly who was the first woman of color in the United States to earn her doctorate in Chemistry.
In 1948, Branson took a leave and spent time at the California Institute of Technology, in the laboratory of the chemist Linus Pauling. There he was assigned work on the structure of proteins, specifically to use his mathematical abilities to determine possible helical structures that would fit both the available X-ray crystallography data and a set of chemical restrictions outlined by Pauling.After some months of work, Branson handed in a report narrowing the possible structures to two helices: a tighter coil Pauling termed "alpha," and a looser helix called "gamma." Branson then returned to Howard to work on other projects. Some months later he received a letter from Pauling along with a draft manuscript of a paper detailing the two helixes, with Branson listed as third author (after Pauling and his assistant Robert Corey, the laboratory's expert in transforming X-ray data into precise models). Pauling asked for suggestions. Branson replied in a letter that it was fine as written, approved submission to the Proceedings of the National Acaademy of Sciences, and asked for 25 preprints when published.
Branson went on to a significant career, eventually serving as president of Central State University in Wilberforce, Ohio, from 1968–1970, and then president of Lincoln University until his retirement in 1985. He was active in increasing federal funding for higher education, and helped found the National Association for Equal Opportunity in Higher Education in 1990 .
In 1984 Branson wrote Pauling biographers Victor and Mildred Goertzel implying that his contribution to the alpha helix had been greater than the final paper indicated. "I took my work to Pauling who told me that he thought they [the proposed alpha and gamma helixes] were too tight, that he thought that a protein molecule should have a much larger radius so that water molecules could fit down inside and cause the protein to swell," he wrote. "I went back and worked unsuccessfully to find such a structure." When he received Pauling's note with the draft manuscript, Branson wrote, "I interpreted this letter as establishing that the alpha and gamma in my paper were correct and that the subsequent work done was cleaning up or verifying. The differences were nil." He added in his letter to the Goertzels that he "resented" the later attention lavished on Pauling and Corey.The conservative watchdog group Accuracy in Media referred to the incident in an attack on Pauling in 1994. The available records, historical context, knowledge of the personalities involved, and studies of Pauling's laboratory and methods at the time have led most historians to accord greater credit to Pauling and Corey.
The alpha helix (α-helix) is a common motif in the secondary structure of proteins and is a right hand-helix conformation in which every backbone N−H group hydrogen bonds to the backbone C=O group of the amino acid located three or four residues earlier along the protein sequence.
Francis Harry Compton Crick was a British molecular biologist, biophysicist, and neuroscientist. In 1953, he co-authored with James Watson the academic paper proposing the double helix structure of the DNA molecule. Together with Watson and Maurice Wilkins, he was jointly awarded the 1962 Nobel Prize in Physiology or Medicine "for their discoveries concerning the molecular structure of nucleic acids and its significance for information transfer in living material". The results were based partly on fundamental studies done by Rosalind Franklin, Raymond Gosling and Wilkins.
Protein secondary structure is the three dimensional form of local segments of proteins. The two most common secondary structural elements are alpha helices and beta sheets, though beta turns and omega loops occur as well. Secondary structure elements typically spontaneously form as an intermediate before the protein folds into its three dimensional tertiary structure.
Linus Carl Pauling was an American chemist, biochemist, chemical engineer, peace activist, author, and educator. He published more than 1,200 papers and books, of which about 850 dealt with scientific topics. New Scientist called him one of the 20 greatest scientists of all time, and as of 2000, he was rated the 16th most important scientist in history. For his scientific work, Pauling was awarded the Nobel Prize in Chemistry in 1954. For his peace activism, he was awarded the Nobel Peace Prize in 1962. He is one of four individuals to have won more than one Nobel Prize. Of these, he is the only person to have been awarded two unshared Nobel Prizes, and one of two people to be awarded Nobel Prizes in different fields, the other being Marie Curie. He was married to the American human rights activist Ava Helen Pauling.
Maurice Hugh Frederick Wilkins was a New Zealand-born British physicist and molecular biologist, and Nobel laureate whose research contributed to the scientific understanding of phosphorescence, isotope separation, optical microscopy and X-ray diffraction, and to the development of radar. He is best known for his work at King's College London on the structure of DNA.
Sir William Lawrence Bragg, was an Australian-born British physicist and X-ray crystallographer, discoverer (1912) of Bragg's law of X-ray diffraction, which is basic for the determination of crystal structure. He was joint recipient of the Nobel Prize in Physics in 1915, "For their services in the analysis of crystal structure by means of X-ray"; an important step in the development of X-ray crystallography.
A coiled coil is a structural motif in proteins in which 2–7 alpha-helices are coiled together like the strands of a rope. Many coiled coil-type proteins are involved in important biological functions such as the regulation of gene expression, e.g. transcription factors. Notable examples are the oncoproteins c-Fos and c-jun, as well as the muscle protein tropomyosin.
Alpha Chi Sigma (ΑΧΣ) is a professional fraternity specializing in the fields of the chemical sciences. It has both collegiate and professional chapters throughout the United States consisting of both men and women and numbering more than 70,000 members. The fraternity aims to bring together students and professionals pursuing a wide variety of chemistry-related careers.
In biochemistry, a Ramachandran plot, originally developed in 1963 by G. N. Ramachandran, C. Ramakrishnan, and V. Sasisekharan, is a way to visualize energetically allowed regions for backbone dihedral angles ψ against φ of amino acid residues in protein structure. The figure on the left illustrates the definition of the φ and ψ backbone dihedral angles. The ω angle at the peptide bond is normally 180°, since the partial-double-bond character keeps the peptide planar. The figure in the top right shows the allowed φ,ψ backbone conformational regions from the Ramachandran et al. 1963 and 1968 hard-sphere calculations: full radius in solid outline, reduced radius in dashed, and relaxed tau (N-Cα-C) angle in dotted lines. Because dihedral angle values are circular and 0° is the same as 360°, the edges of the Ramachandran plot "wrap" right-to-left and bottom-to-top. For instance, the small strip of allowed values along the lower-left edge of the plot are a continuation of the large, extended-chain region at upper left.
"Molecular Structure of Nucleic Acids: A Structure for Deoxyribose Nucleic Acid" was the first article published to describe the discovery of the double helix structure of DNA, using X-ray diffraction and the mathematics of a helix transform. It was published by Francis Crick and James D. Watson in the scientific journal Nature on pages 737–738 of its 171st volume.
William Thomas Astbury FRS was an English physicist and molecular biologist who made pioneering X-ray diffraction studies of biological molecules. His work on keratin provided the foundation for Linus Pauling's discovery of the alpha helix. He also studied the structure for DNA in 1937 and made the first step in the elucidation of its structure.
Maurice Loyal Huggins was a scientist who independently conceived the idea of hydrogen bonding and who was an early advocate for their role in stabilizing protein secondary structure. An important polymer theory, Flory–Huggins theory, is also named after him.
A pi helix is a type of secondary structure found in proteins. Discovered by crystallographer Barbara Low in 1952 and once thought to be rare, short π-helices are found in 15% of known protein structures and are believed to be an evolutionary adaptation derived by the insertion of a single amino acid into an α-helix. Because such insertions are highly destabilizing, the formation of π-helices would tend to be selected against unless it provided some functional advantage to the protein. π-helices therefore are typically found near functional sites of proteins.
A 310 helix is a type of secondary structure found in proteins and polypeptides. Of the numerous protein secondary structures present, the 310-helix is the fourth most common type observed; following α-helices, β-sheets and reverse turns. 310-helices constitute nearly 10–15% of all helices in protein secondary structures, and are typically observed as extensions of α-helices found at either their N- or C- termini. Because of the α-helices tendency to consistently fold and unfold, it has been proposed that the 310-helix serves as an intermediary conformation of sorts, and provides insight into the initiation of α-helix folding.
Robert Brainard Corey was an American biochemist, mostly known for his role in discovery of the α-helix and the β-sheet with Linus Pauling. Also working with Pauling was Herman Branson. Their discoveries were remarkably correct, with even the bond lengths being accurate until about 40 years later. The α-helix and β-sheet are two structures that are now known to form the backbones of many proteins.
Alpha sheet is an atypical secondary structure in proteins, first proposed by Linus Pauling and Robert Corey in 1951. The hydrogen bonding pattern in an alpha sheet is similar to that of a beta sheet, but the orientation of the carbonyl and amino groups in the peptide bond units is distinctive; in a single strand, all the carbonyl groups are oriented in the same direction on one side of the pleat, and all the amino groups are oriented in the same direction on the opposite side of the sheet. Thus the alpha sheet accumulates an inherent separation of electrostatic charge, with one edge of the sheet exposing negatively charged carbonyl groups and the opposite edge exposing positively charged amino groups. Unlike the alpha helix and beta sheet, the alpha sheet configuration does not require all component amino acid residues to lie within a single region of dihedral angles; instead, the alpha sheet contains residues of alternating dihedrals in the traditional right-handed (αR) and left-handed (αL) helical regions of Ramachandran space. Although the alpha sheet is only rarely observed in natural protein structures, it has been speculated to play a role in amyloid disease and it was found to be a stable form for amyloidogenic proteins in molecular dynamics simulations. Alpha sheets have also been observed in X-ray crystallography structures of designed peptides.
Harvey Akio Itano was an American biochemist best known for his work on the molecular basis of sickle cell anemia and other diseases. In collaboration with Linus Pauling, Itano used electrophoresis to demonstrate the difference between normal hemoglobin and sickle cell hemoglobin; their 1949 paper "Sickle Cell Anemia, a Molecular Disease" was a landmark in both molecular medicine and protein electrophoresis.
In addition to the variety of verified DNA structures, there have been a range of obsolete models that have either been disproven, or lack evidence.
Victor Goertzel was an American psychologist, author, and activist who stood up for Japanese internees in the United States during World War II. He wrote the book Cradles of Eminence in 1962 with his wife Mildred about the childhoods of accomplished people. Ted Goertzel is their son. He was a civil libertarian.
David W. Green was a crystallographer at the Medical Research Council Unit for the Study of the Molecular Structure of Biological Systems, Cavendish Laboratory, University of Cambridge.