Download MendeleyCrystal structure of bovine procarboxypeptidase A-S6 subunit III, a highly structured truncated zymogen E.
Pignol, D., Gaboriaud, C., Michon, T., Kerfelec, B., Chapus, C., Fontecilla-Camps, J.C.(1994) EMBO J 13: 1763-1771
- PubMed: 8168476
- DOI: https://doi.org/10.1002/j.1460-2075.1994.tb06444.x
- Primary Citation of Related Structures:
1FON - PubMed Abstract:
Subunit III, a defective serine endopeptidase lacking the typical N-terminal hydrophobic dipeptide is secreted by the pancreas of ruminant species as part of the bovine ternary complex procarboxypeptidase A-S6. Two monoclinic crystal forms were obtained and subsequently used to solve its X-ray structure. The highest resolution model of subunit III was refined at 1.7 A resolution to a crystallographic R-factor of 18.4%, with r.m.s. bond deviations from ideality of 0.012 A. About 80% of the model presents the characteristic architecture of trypsin-like proteases. The remaining zones, however, have well-defined, unique conformations. The regions from residues 70 to 80 and from 140 to 155 present maximum distances of 16 and 18 A relative to serine proteases and zymogens. Comparisons with the structures of porcine elastase 1 and chymotrypsinogen A indicate that the specific binding pocket of subunit III adopts a zymogen-like conformation and thus provide a basis for its inactivity. In general, the structural analysis of subunit III strongly suggests that it corresponds to a truncated version of a new class of highly structured elastase-like zymogen molecules. Based on the structures of subunit III and elastase 1, it is concluded that large concerted movements are necessary for the activation of zymogen E.
Organizational Affiliation:
Laboratoire de Cristallographie et de Cristallogénès des Protéines, Institut de Biologie Structurale, Grenoble, France.
