1r5c
From Proteopedia
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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 with as ligand. Active as Pancreatic ribonuclease, with EC number 3.1.27.5 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 Thu Feb 21 14:47:19 2008
