1f57
From Proteopedia
CARBOXYPEPTIDASE A COMPLEX WITH D-CYSTEINE AT 1.75 A
Overview
D-Cysteine differs from the antiarthritis drug D-penicillamine by only two methyl groups on the beta-carbon yet inhibits carboxypeptidase A (CPD) by a distinct mechanism: D-cysteine binds tightly to the active site zinc, while D-penicillamine catalyzes metal removal. To investigate the structural basis for this difference, we solved the crystal structure of carboxypeptidase A complexed with D-cysteine (D-Cys) at 1.75-A resolution. D-Cys binds the active site zinc with a sulfur ligand and forms additional interactions with surrounding side chains of the enzyme. The structure explains the difference in potency between D-Cys and L-Cys and provides insight into the mechanism of D-penicillamine inhibition. D-Cys binding induces a concerted motion of the side chains around the zinc ion, similar to that found in other carboxypeptidase-inhibitor crystal structures and along a limited path. Analysis of concerted motions of CPD and CPD-inhibitor crystal structures reveals a clustering of these structures into distinct groups. Using the restricted conformational flexibility of a drug target in this type of analysis could greatly enhance efficiency in drug design.
About this Structure
1F57 is a Single protein structure of sequence from Bos taurus. Full crystallographic information is available from OCA.
Reference
Crystal structure of carboxypeptidase A complexed with D-cysteine at 1.75 A - inhibitor-induced conformational changes., van Aalten DM, Chong CR, Joshua-Tor L, Biochemistry. 2000 Aug 22;39(33):10082-9. PMID:10955996 Page seeded by OCA on Fri May 2 15:54:54 2008
