Carl George Niemann (July 6, 1908 – April 29, 1964) was an American biochemist who worked extensively on the chemistry and structure of proteins, publishing over 260 research papers.
He is known, with Max Bergmann, for proposing the Bergmann-Niemann hypothesis that proteins consist of 288 residue polypeptides or multiples thereof with periodic sequences of amino acids, and for contributing to the downfall of the cyclol model of protein structure.
They also suggested that in the polypeptides of a given protein, amino acids occurred in a regular, repeating pattern; for example, they proposed that silk fibroin, known to consist mainly of glycine and alanine, had a sequence of glycine-alanine-glycine-[other], with the glycine/alanine pattern making up three of every four amino acids and other residues falling periodically into the fourth spot.
[2][3] After his work at the Rockefeller Institute and at the University College Hospital as a Rockefeller Foundation Fellow, and with strong support from Warren Weaver, Niemann joined Linus Pauling's Crellin Laboratory at CalTech in 1938.
In 1939, Niemann and Linus Pauling published a strong critique of Dorothy Wrinch's cyclol hypothesis of protein structure, which held that globular proteins formed inter-linked, cage-like polyhedral structures.