An Investigation of the Structures of Some Crystalline Peptides and the Synthetic Polypeptide Poly-γ-Methyl-L-Glutamate

Citation

Yakel, Harry L. (1952) An Investigation of the Structures of Some Crystalline Peptides and the Synthetic Polypeptide Poly-γ-Methyl-L-Glutamate. Dissertation (Ph.D.), California Institute of Technology. doi:10.7907/JK0E-GS59. https://resolver.caltech.edu/CaltechTHESIS:10052017-093432115

Abstract

The unit cell dimensions and space groups of α-triglycine, triglycine hydrate and NN'-diglycyl-L-cystine have been determined by X-ray methods. The complete structure of NN'-diglycyl-L-cystine has also been elucidated. The structural nature of the "disulfide bridge", which forms a part of this molecule, is described. Bond lengths and angles are of the usual size found in previous peptide molecules, but there are several weak hydrogen bonds particularly in the amide groups of the molecule.

An investigation of the fibrous synthetic polypeptide poly-γ-methyl-L-glutamate is reported. X-ray diffraction data from well oriented α fibers of this substance have been indexed on the basis of a hexagonal cell. The intensities of the X-ray reflections for two layer lines have been interpreted using the 3.6 residue α-helix model proposed by Pauling and Corey. A resume of the data appears to support this model for the polypeptide chain in poly-γ-methyl-L-glutamate.

Thesis Files