1bvi

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spinqualitylabelsall models 1bvi, resolution 1.90Å Show:Asymmetric Unit Biological Assembly Drag the structure with the mouse to rotate   Export Animated Image

RIBONUCLEASE T1 (WILDTYPE) COMPLEXED WITH 2'GMP

Overview

The reoccurrence of water molecules in crystal structures of RNase T1 was, investigated. Five waters were found to be invariant in RNase T1 as well, as in six other related fungal RNases. The structural, dynamical, and, functional characteristics of one of these conserved hydration sites, (WAT1) were analyzed by protein engineering, X-ray crystallography, and, (17)O and 2H nuclear magnetic relaxation dispersion (NMRD). The position, of WAT1 and its surrounding hydrogen bond network are unaffected by, deletions of two neighboring side chains. In the mutant Thr93Gln, the, Gln93N epsilon2 nitrogen replaces WAT1 and participates in a similar, hydrogen bond network involving Cys6, Asn9, Asp76, and Thr91. The ability, of WAT1 to form four hydrogen bonds may explain why evolution has, preserved a water molecule, rather than a side-chain atom, at the center, of this intricate hydrogen bond network. Comparison of the (17)O NMRD, profiles from wild-type and Thr93Gln RNase T1 yield a mean residence time, of 7 ns at 27 degrees C and an orientational order parameter of 0.45. The, effects of mutations around WAT1 on the kinetic parameters of RNase T1 are, small but significant and probably relate to the dynamics of the active, site.

About this Structure

1BVI is a Single protein structure of sequence from Aspergillus oryzae with CA and 2GP as ligands. Active as Ribonuclease T(1), with EC number 3.1.27.3 Full crystallographic information is available from OCA.

Reference

Dissection of the structural and functional role of a conserved hydration site in RNase T1., Langhorst U, Loris R, Denisov VP, Doumen J, Roose P, Maes D, Halle B, Steyaert J, Protein Sci. 1999 Apr;8(4):722-30. PMID:10211818

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