1avf

Publication Abstract from PubMed

The crystal structure of an activation intermediate of human gastricsin has been determined at 2.4 A resolution. The human digestive enzyme gastricsin (pepsin C) is an aspartic proteinase that is synthesized as the inactive precursor (zymogen) progastricsin (pepsinogen C or hPGC). In the zymogen, a positively-charged N-terminal prosegment of 43 residues (Ala 1p-Leu 43p; the suffix 'p' refers to the prosegment) sterically prevents the approach of a substrate to the active site. Zymogen conversion occurs in an autocatalytic and stepwise fashion at low pH through the formation of intermediates. The structure of the non-covalent complex of a partially-cleaved peptide of the prosegment (Ala 1p-Phe 26p) with mature gastricsin (Ser 1-Ala 329) suggests an activation pathway that may be common to all gastric aspartic proteinases.

Structural characterization of activation 'intermediate 2' on the pathway to human gastricsin.,Khan AR, Cherney MM, Tarasova NI, James MN Nat Struct Biol. 1997 Dec;4(12):1010-5. PMID:9406551^[1]

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.