Is gamma-chymotrypsin a tetrapeptide acyl-enzyme adduct of alpha-chymotrypsin?
Refinement of the structure of gamma-chymotrypsin based on X-ray crystallographic data to 1.6-A resolution has confirmed the overall conformation of the molecule as reported previously [Cohen, G. H., Silverton, E. W., & Davies, D. R. (1981) J. Mol. Biol. 148, 449-479]. In addition, the new refinement suggests that gamma-chymotrypsin, which is operationally defined by its crystalline habit, may not be the free enzyme but rather a complex, possibly an acyl-enzyme adduct, with the tetrapeptide Pro-Gly-Ala-Tyr (or a close homologue). The crystallographic refinement provides a detailed geometrical description of the enzyme-substrate-solvent interactions that occur in the presumptive adduct.
Dixon
M M
MM
Institute of Molecular Biology, University of Oregon, Eugene 97403.
Matthews
B W
BW
D002918:Chymotrypsin / Q000378:metabolism; D006860:Hydrogen Bonding; D046911:Macromolecular Substances; D008958:Models, Molecular; D011487:Protein Conformation; D014961:X-Ray Diffraction / Q000379:methods
D046911:Macromolecular Substances; D002918:Chymotrypsin