1FON

CRYSTAL STRUCTURE OF BOVINE PROCARBOXYPEPTIDASE A-S6 SUBUNIT III, A HIGHLY STRUCTURED TRUNCATED ZYMOGEN E

Summary for 1FON

• Entry DOI: 10.2210/pdb1fon/pdb
• Descriptor: PROCARBOXYPEPTIDASE A-S6 (2 entities in total)
• Functional Keywords: truncated zymogen e, serine protease
• Biological source: Bos taurus (cattle)
• Total number of polymer chains: 2
• Total formula weight: 51767.80

Authors

Pignol, D.C.,Gaboriaud, T.,Michon, B.,Kerfelec, B.,Chapus, C.,Fontecilla-Camps, J.C. (deposition date: 1996-02-01, release date: 1996-10-14, Last modification date: 2024-10-16)

Primary citation

Pignol, D.,Gaboriaud, C.,Michon, T.,Kerfelec, B.,Chapus, C.,Fontecilla-Camps, J.C.
Crystal structure of bovine procarboxypeptidase A-S6 subunit III, a highly structured truncated zymogen E.
EMBO J., 13:1763-1771, 1994

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.

PubMed: 8168476

Experimental method

X-RAY DIFFRACTION (1.7 Å)