1r5c
From Proteopedia
X-ray structure of the complex of Bovine seminal ribonuclease swapping dimer with d(CpA)
Overview
Bovine seminal ribonuclease (BS-RNase) is a unique member of the pancreatic-like ribonuclease superfamily. This enzyme exists as two conformational isomers with distinctive biological properties. The structure of the major isomer is characterized by the swapping of the N-terminal segment (MxM BS-RNase). In this article, the crystal structures of the ligand-free MxM BS-RNase and its complex with 2'-deoxycitidylyl(3',5')-2'-deoxyadenosine derived from isomorphous crystals have been refined. Interestingly, the comparison between this novel ligand-free form and the previously published sulfate-bound structure reveals significant differences. In particular, the ligand-free MxM BS-RNase is closer to the structure of MxM BS-RNase productive complexes than to the sulfate-bound form. These results reveal that MxM BS-RNase presents a remarkable flexibility, despite the structural constraints of the interchain disulfide bridges and the swapping of the N-terminal helices. These findings have important implications to the ligand binding mechanism of MxM BS-RNase. Indeed, a population shift rather than a substrate-induced conformational transition may occur in the MxM BS-RNase ligand binding process.
About this Structure
1R5C is a Single protein structure of sequence from Bos taurus. Full crystallographic information is available from OCA.
Reference
Population shift vs induced fit: the case of bovine seminal ribonuclease swapping dimer., Merlino A, Vitagliano L, Sica F, Zagari A, Mazzarella L, Biopolymers. 2004 Apr 15;73(6):689-95. PMID:15048772 Page seeded by OCA on Sat May 3 07:05:58 2008
