1lra
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(New page: 200px<br /><applet load="1lra" size="450" color="white" frame="true" align="right" spinBox="true" caption="1lra, resolution 1.9Å" /> '''CRYSTALLOGRAPHIC STUD...)
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Revision as of 18:41, 20 November 2007
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CRYSTALLOGRAPHIC STUDY OF GLU 58 ALA RNASE T1(ASTERISK)2'-GUANOSINE MONOPHOSPHATE AT 1.9 ANGSTROMS RESOLUTION
Overview
Glu58 is known to participate in phosphodiester transesterification, catalyzed by the enzyme RNase T1. For Glu58 RNase T1, an altered mechanism, has been proposed in which His40 replaces Glu58 as the base catalyst, [Steyaert, J., Hallenga, K., Wyns, L., & Stanssens, P. (1990) Biochemistry, 29, 9064-9072]. Glu58Ala Rnase T1 has been cocrystallized with guanosine, 2'-monophosphate (2'-GMP). The crystals are of space group P2(1), with one, molecule per asymmetric unit (a = 32.44 A, b = 49.64 A, c = 26.09 A, beta, = 99.17 degrees). The three-dimensional structure of the enzyme was, determined to a nominal resolution of 1.9 A, yielding a crystallographic R, factor of 0.178 for all X-ray data. Comparison of this structure with, wild-type structures leads to the following conclusions. The minor changes, apparent in the tertiary structure can be explained by either the mutation, of Glu58 or by the change in the space group. In the active site, the, extra space available through the mutation of Glu58 is occupied by the, phosphate group (after a reorientation) and by a solvent molecule, replacing a carboxylate oxygen of Glu58. This solvent molecule is a, candidate for participation in the altered mechanism of this mutant, enzyme. Following up on a study of conserved water sites in RNase T1, crystallized in space group P2(1)2(1)2(1) [Malin, R., Zielenkiewicz, P., &, Saenger, W. (1991) J. Mol. Biol. 266, 4848-4852], we investigated the, hydration structure for four different packing modes of RNase T1.(ABSTRACT, TRUNCATED AT 250 WORDS)
About this Structure
1LRA is a Single protein structure of sequence from Aspergillus oryzae with NA and 2GP as ligands. Active as Ribonuclease T(1), with EC number 3.1.27.3 Full crystallographic information is available from OCA.
Reference
Crystallographic study of Glu58Ala RNase T1 x 2'-guanosine monophosphate at 1.9-A resolution., Pletinckx J, Steyaert J, Zegers I, Choe HW, Heinemann U, Wyns L, Biochemistry. 1994 Feb 22;33(7):1654-62. PMID:7906540
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