American chemist Linus Pauling has made important contributions to a number of fields, including the structure of proteins and other biologically important molecules, mineralogy, quantum mechanics, the nature of mental disorders, nuclear structure, and nutrition. He determined the molecular structure of more than 225 substances using an electron diffraction technique. Pauling was the first to construct the alpha helical structure of a protein. Pauling developed the theory of complementarity and used it to explain enzyme reactions and how genes might act as templates for the formation of enzymes. Using this theory, he studied the relationship between molecular abnormality and hereditary, and was able to determine that sickle cell anemia is caused by the change of a single amino acid in a hemoglobin molecule. Linus Pauling is the only person ever to win two unshared Nobel Prizes. His 1954 Nobel Prize for chemistry was given in recognition of his work on the nature of the chemical bond, while the 1963 Nobel Peace Prize was awarded for his efforts to bring about an end to the atmospheric testing of nuclear weapons.
Linus Carl Pauling was born in Portland, Oregon. In the fall of 1917, Pauling entered Oregon Agricultural College (OAC), now Oregon State University, in Corvallis. After graduation from OAC in 1922 with a B.S. in chemical engineering, Pauling entered the California Institute of Technology (Cal Tech) in Pasadena. Pauling was awarded his Ph.D in chemistry summa cum laude in 1925 and decided to continue his studies in Europe where he learned about the new field of quantum mechanics. The science of quantum mechanics, less than a decade old at the time, is based on the revolutionary concept that particles can sometimes have wave-like properties, and waves can sometimes best be described as if they consisted of massless particles.
He left Zurich in the summer of 1927, and returned to Cal Tech, where Pauling took up his new post as Assistant Professor of Theoretical Chemistry. During Pauling's first few years as a professor at the college, he worked on the X-ray analysis of crystals, but also began to spend more time on the quantum mechanical study of atoms and molecules. In the summer of 1930, Pauling traveled through Europe learning about the use of electron diffraction techniques to analyze crystalline materials. Upon his return to Cal Tech, Pauling showed one of his students, L. O. Brockway, how the technique worked and had him build an electron diffraction instrument. Over the next 25 years, Pauling, Brockway, and their colleagues used the diffraction technique to determine the molecular structure of more than 225 substances.
By the mid-1930s, Pauling began studying the structure of biological molecules. These molecules are complex substances that are found in living organisms and can contain thousands of atoms in each molecule rather than the relatively simple molecules that Pauling had studied previously that contained only twenty or thirty atoms. The first substance that attracted his attention was the hemoglobin molecule. Hemoglobin is the substance that transports oxygen through the bloodstream. Pauling's initial work with hemoglobin, carried out with a graduate student Charles Coryell, produced some fascinating results. Their research showed that the hemoglobin molecule undergoes significant structural change when it picks up or loses an oxygen atom. In order to continue his studies, Pauling decided he needed to know much more about the structure of hemoglobin, in particular, and proteins, in general.
Fortunately, he was already familiar with the primary technique by which this research could be done: x-ray diffraction analysis. The problem was that x-ray diffraction analysis of protein is far more difficult than it is for the crystalline minerals Pauling had earlier worked with. In fact, the only suitable x-ray pictures of protein available in the 1930s were those of the British crystallographer, William Astbury. Pauling decided, therefore, to see if the principles of quantum mechanics could be applied to Astbury's photographs to obtain the molecular structures of proteins.
The earliest efforts along these lines by Pauling and Coryell in 1937 were unsuccessful. None of the molecular structures they drew based on quantum mechanical principles could account for patterns like those in Astbury's photographs. It was not until eleven years later that Pauling finally realized what the problem was. The mathematical analysis and the models it produced were correct. It was Astbury's patterns that were incorrect. In the pictures Astbury had taken, protein molecules tilted slightly from the expected position. By the time Pauling recognized this problem, he had already developed a satisfactory molecular model for hemoglobin. The model was that of a helix, or spiral-staircase-like structure in which a chain of atoms is wrapped around a central axis. Pauling had developed the model by using a research technique on which he frequently depended--model building. He constructed atoms and groups of atoms out of pieces of paper and cardboard and then tried to fit them together in ways that would conform to quantum mechanical principles. Not surprisingly, Pauling's technique was also adopted by two contemporaries, Francis Crick and James Watson, in their solution of the DNA molecule puzzle, a problem that Pauling himself nearly solved.
Pauling also turned his attention to other problems of biological molecules. In 1939, for example, he developed the theory of complementarity and applied it the subject of enzyme reactions. He later used the same theory to explain how genes might act as templates for the formation of enzymes. In 1945, Pauling attacked and solved an important medical problem by using chemical theory. He demonstrated that the genetic disorder known as sickle cell anemia is caused by the change of a single amino acid in the hemoglobin molecule.
At the age of 65, Linus Pauling began to examine the possible therapeutic effects of vitamin C. Pauling was introduced to the potential value of vitamin C in preventing colds by biochemist Irwin Stone in 1966. He soon became intensely interested in the topic and summarized his views in a 1970 book, Vitamin C and The Common Cold. Before long, he became convinced that the vitamin was also helpful in preventing cancer.
Pauling's long association with Cal Tech ended in 1964, at least partly because of his active work in the peace movement. He accepted an appointment at the Study of Democratic Institutions in Santa Barbara for four years and then moved on to the University of California at San Diego for two more. In 1969, he moved to Stanford University where he remained until his compulsory retirement in 1974. In that year, Pauling and some colleagues and friends founded the Institute of Orthomolecular Medicine, later to be renamed the Linus Pauling Institute of Science and Medicine, in Palo Alto. Pauling died of cancer at his ranch in California in 1994.
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