Famous Scientist in Genetic Research: Linus Pauling

Linus_Pauling

Linus Pauling (Wikimedia)

Linus Pauling (February 28, 1901 – August 19, 1994) has already established himself as one of the premiere scientists in chemistry when he shifted his focus and became a vital force in genetic and biochemical research during the 20th century.  His interest and proficiency in chemistry at a young age led to his achievements in the fields of chemistry, quantum mechanics, biochemistry, genetics, and medical research.

Chemistry

While in Oregon State University (OSU), Pauling became interested in the electronic structure of atoms and how they bonded to form molecules. This interest led him to delve into the relationships between chemical and physical properties of substances and their atomic structure. Thus, with this research focus, he became one of the progenitors of quantum chemistry.

His interest in mathematical chemistry and physics continued. He entered graduate school at the California Institute of Technology, with crystal structure of minerals being his primary research interest. He published seven papers on the subject during his post-graduate stay in Caltech and graduated summa cum laude in 1925 with a doctorate degree in chemistry having strong minors in mathematics and physics.

Eager to learn from the greatest scientific minds of the era, Pauling travelled to Europe and studied under Neils Bohr, Arnold Sommerfeld and Erwin Schrodinger. These men were the leading scientists in quantum mechanics, bringing their individual mathematical and physics experience into this new field of science. Quantum mechanics dealt primarily with the inner workings of atoms and their components and how they interacted to form substances, thus, it was an important step in Pauling’s own research on the electronic structure of atoms and molecules.

Building on his experience in Europe, Pauling continued his research into crystal diffraction initially using x-rays but eventually utilizing electron diffraction technology obtained from Europe. His work encompassed charting bond angles as well as atomic arrangements in crystals. He also delved into ionic bonding, confirming the theoretical concept of electron transfer between ionic atoms to form bonds. It was here that he developed “Pauling’s Five Rules” which provided the theoretical framework for defining the structures of complex compounds, particularly silicoids and metals. His research postulated that magnetic properties play a vital role in both covalent and ionic bonding.

Another of Pauling’s major contributions was in the field of electronegativity. He constructed the electronegativity scale with elements having smaller electronegativity being closer in approaching a pure covalent bond. Additionally, he proposed two important concepts in chemistry, bond orbital hybridization and bond resonance. This allowed scientists to account for structural patterns that occurred but were then unexplainable by empirical formula, thus opening the way for theoretical research in structural stability and geometry.

Pauling was the single unstoppable force in chemistry during the era, having the ability to theoretically predict the structure of undiscovered compounds using his “stochastic method”. His experience and knowledge coupled with his creative mind enabled him to visualize new substances based on rules and established patterns. This proficiency in theoretical mathematics on the mechanics of atoms and molecules yielded fifty papers during his five year tenure as a professor at Cal-tech. Due to his work on the nature of chemical bonds Linus Pauling became the first recipient of the Langmuir award for the most significant scientific contribution by a person less than thirty years of age.
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Biochemistry and Genetics

With his background in chemical structures, quantum mechanics and diffraction, Pauling had no difficulty shifting his focus to biological studies during the 1930’s.  His previous work on metallic compounds and crystals gave him a novel approach when tackling the chemistry of biological molecules. This produced the 1940 research on the properties of hemoglobin. His next work on the interactions between antigens and antibodies was the start of his investigations regarding specificity in biochemistry.

Pauling postulated that biological specificity was present at the molecular level, with a molecule of a particular shape fitting into a complementary molecule. This “hand in glove” theory again reaped publications and awards finally leading to Pauling’s proposal in 1946 that the gene might be composed of two complementary strands. Two years later, this idea would form the basis for the alpha helix. Pauling, together with Robert Corey and Herman Brandon proposed that two chains of polypeptides containing complementary strands of amino acids would each coil around each other, resulting in a right handed coil known as the “alpha helix”.

The alpha helix was a step into the search for the structure of DNA. Leading scientists worldwide were vying for the honor of becoming the first to correctly identify DNA’s makeup and structure. Linus Puling was no exception and but for a quirk of fate, he would have had ample chance in the race. Sadly, troubles with his political opinions led the U.S. government to deny him a passport just when he was heading to a scientific convention in England. By chance, this was the same convention where Watson and Crick first saw Rosalind Franklin and Raymond Gosling’s “photo 51”, giving them an idea of DNA’s double helix structure. Pauling put forth his own, triple helix theory based on the limited resources available to him.

Linus Pauling had another significant contribution, this time in the field of molecular genetics. Together with Harvey Itano, S.J. Singer and Ibert Wells, Pauling published a study giving a molecular description to the disease sickle cell anemia. His experience in working with hemoglobin as well as his theory of specificity in biological molecules led him to believe that sickle cells were caused by two complementary sites within an abnormal hemoglobin, thus attracting each other, res Entitled “Sickle Cell Anemia, a Molecular disease” and published in Science, Pauling and his co-authors used electrophoreses to demonstrate the presence of a modified form of hemoglobin in those who have the disease, while also showing that carrier have both normal and modified forms. This paper was the first to exhibit the role of Mendelian inheritance in determining a protein’s physical properties. It showcased the first genetic disease, accurately showing hereditary patterns and the presence of unaffected carriers. It also showed that genes were not limited to expressions of presence and absence of enzymes but could affect protein properties as well.

From chemistry to biology to genetics, Linus Pauling has impacted most of the scientific revolutions in these three fields. He showed that science actually is interdisciplinary and that techniques, methods and knowledge from one branch can be utilized with success in others.

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References

  • Pauling, Linus, Harvey A. Itano, S. J. Singer, Ibert C. Wells (1949). “Sickle Cell Anemia, a Molecular Disease”. Science 110 (2865): 543–548.
  • Nobel Lectures (1964) Linus Pauling Biography, Chemistry 1942-1962, Elsevier Publishing Company, Amsterdam, from Nobel Prize Foundation Linus Pauling Biography. Nobelprize.org. 9 Jun 2011 http://nobelprize.org/nobel_prizes/chemistry/laureates/1954/pauling-bio.html