Linus Pauling
“for his research into the nature of the chemical bond and its application to the elucidation of the structure of complex substances”
Anchor structure: Hemoglobin subunit beta View 3D structure → UniProt P68871 · PDB 2HHB
Linus Pauling figured out how proteins fold. He showed that they curl into a spiral he called the alpha helix. This shape lets proteins do many jobs in your cells. Pauling also found that sickle cell anemia is caused by a tiny change in one protein. He helped start the field of how molecules cause disease.
Why it still matters: Today, biologists still describe protein shapes using the alpha helix. The same rules now help computers like AlphaFold predict how new proteins will fold.
In 1948 Pauling proposed the alpha helix. It is a spiral pattern of the protein backbone, held together by hydrogen bonds. He worked it out without seeing a real protein. He used rules about chemical bonds and angles. Five years later, X-ray work confirmed his model. Pauling also showed that sickle cell disease comes from a single change to the hemoglobin protein. It was the first time anyone linked a disease to a specific molecular defect. The Nobel honoured both lines of work — a model of how proteins fold, and a framework for understanding disease at the molecular level.
Why it still matters: Modern protein-prediction tools like AlphaFold start from the same backbone geometry Pauling worked out by hand. Sickle cell research has moved from observation to gene therapy — Casgevy, approved in 2023, edits the gene Pauling's electrophoresis pointed at seventy years earlier.
Pauling's 1948 alpha-helix model predicted a regular structure with ~3.6 residues per turn, stabilised by main-chain hydrogen bonds along the helix axis. He derived the geometry from peptide-bond planarity arguments — partial double-bond character forcing a planar amide — without a single X-ray structure of a protein to guide him. The model was confirmed by Perutz's polarised X-ray diffraction within two years. The same theoretical reasoning produced the beta sheet. Independently, Pauling and Itano (1949) demonstrated that haemoglobin from sickle-cell patients migrated differently on electrophoresis than normal haemoglobin, establishing sickle-cell anaemia as the first 'molecular disease' — a phrase Pauling coined. The 1954 prize cited bonding work broadly, including its application to complex biological substances. Pauling later received an unshared Nobel Peace Prize (1962), making him one of only four individuals to hold two Nobels.
Why it still matters: The alpha helix remains the most common secondary structure in folded proteins, accounting for roughly a third of all assigned secondary structure in the PDB. Pauling's molecular-disease framing now applies to every Mendelian disorder in OMIM. The β6 sickle-cell mutation is the target of Casgevy (exa-cel), the first CRISPR-Cas9 therapeutic approved by the FDA (December 2023). AlphaFold's transformer-based predictions are evaluated against the secondary-structure assignments Pauling first proposed.
MS-LS1-3HS-LS1-1