3glj

Publication Abstract from PubMed

A new triclinic crystal structure form of porcine pancreatic procarboxypeptidase B (PCPB) was obtained at higher resolution than the previously known tetragonal crystal structure. This new crystal polymorph has allowed for a corrected, accurate assignment of residues along the polypeptide chain based on the currently available gene sequence information and crystallographic data. The present structure shows unbound PCPB in a distinct molecular packing as compared to the previous benzamidine complexed form. Its catalytically important Tyr248 residue is oriented and hydrogen-bonded to solvent water molecules, and locates the furthest away from the catalytic zinc ion as compared to previous structures. A relatively long stretch of residues flanking Tyr248 and guarding the access to the catalytic zinc ion was found to be sequentially unique to the M14 family of peptidases. Predictions from a normal mode analysis indicated that this stretch of residues belongs to a rigid subdomain in the protein structure. The specific presence of a tyrosyl residue at the most exposed position in this region would allow for a delicate balance between extreme hydrophobicity and hydrophilicity and affect substrate binding and the kinetic efficiency of the enzyme. (c) 2009 Wiley Periodicals, Inc. Biopolymers, 2009.

Analysis of a new crystal form of procarboxypeptidase B: further insights into the catalytic mechanism.,Fernandez D, Boix E, Pallares I, Aviles FX, Vendrell J Biopolymers. 2009 Oct 2. PMID:19802820^[1]

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