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The ribbon of hydrogen bonds and the pseudomolecule in the three‐dimensional structure of globular proteins. III. Bovine pancreatic ribonuclease A and bovine seminal ribonuclease
Author(s) -
Peters David,
Peters Jane
Publication year - 2002
Publication title -
biopolymers
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.556
H-Index - 125
eISSN - 1097-0282
pISSN - 0006-3525
DOI - 10.1002/bip.10265
Subject(s) - hydrogen bond , bovine pancreatic ribonuclease , chemistry , ribonuclease , globular protein , crystallography , molecule , ribbon , monomer , pancreatic ribonuclease , stereochemistry , rna , biochemistry , polymer , organic chemistry , gene , materials science , composite material
The model of the three‐dimensional structure of globular proteins, which is based on a ribbon of hydrogen bonds along the whole of the backbone, is now applied to the comparison between monomeric bovine pancreatic ribonuclease A and dimeric bovine seminal ribonuclease. Some waters are involved in the hydrogen bonding of the ribbon, and the protein molecule plus these waters forms a pseudomolecule. The conformations of the three backbones are essentially identical and the three ribbons of hydrogen bonds are conserved with greater than 90% accuracy. We suggest that the conservation of the backbone conformations of the two molecules is a consequence of the conservation of the ribbons of hydrogen bonds. There are 16 simple mutations between the two molecules, of which 15 involve only side‐chain groups with no more than one hydrogen bond to the backbone. Such mutations are not sufficient to change the ribbon of hydrogen bonds and hence there is no change in the backbone conformation. Generalizing this result, we suggest that the conservation of the ribbon is the reason why single point mutations rarely change the conformation of the backbone of the globular proteins. © 2002 Wiley Periodicals, Inc. Biopolymers 65: 347–353, 2002