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4bir
From Proteopedia
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RIBONUCLEASE T1: FREE HIS92GLN MUTANT
Overview
Histidine-40 is known to participate in phosphodiester transesterification, catalyzed by the enzyme ribonuclease T1. A mutant enzyme with a lysine, replacing the histidine-40 (His40Lys RNase T1) retains considerable, catalytic activity [Steyaert, J., Hallenga, K., Wyns, L., & Stanssens, P., (1990) Biochemistry 29, 9064-9072]. We report on the crystal structures of, His40Lys RNase T1 containing a phosphate anion and a guanosine, 2'-phosphate inhibitor in the active site, respectively. Similar to, previously described structures, the phosphate-containing crystals are of, space group P2(1)2(1)2(1), with one molecule per asymmetric unit (a =, 48.27 A, b = 46.50 A, c = 41.14 A). The complex with 2'-GMP crystallized, in the lower symmetry space group P2(1), with two molecules per asymmetric, unit (a = 49.20 A, b = 48.19 A, c = 40.16 A, beta = 90.26). The crystal, structures have been solved at 1.8- and 2.0-A resolution yielding R values, of 14.5% and 16.0%, respectively. Comparison of these His40Lys structures, with the corresponding wild-type structures, containing 2'-GMP [Arni, R., Heinemann, U., Tokuoka, R., & Saenger, W. (1988) J. Biol. Chem. 263, 15358-15368] and vanadate [Kostrewa, D., Hui-Woog Choe, Heinemann, U., &, Saenger, W. (1989) Biochemistry 28, 7692-7600] in the active site, respectively, leads to the following conclusions. First, the His40Lys, mutation causes no significant changes in the overall structure of RNase, T1; second, the Lys40 side chains in the mutant structures occupy roughly, the same space as His40 in the corresponding wild-type RNase T1, structures.(ABSTRACT TRUNCATED AT 250 WORDS)
About this Structure
4BIR is a Single protein structure of sequence from Aspergillus oryzae with as ligand. Active as Ribonuclease T(1), with EC number 3.1.27.3 Known structural/functional Site: . Full crystallographic information is available from OCA.
Reference
Role of histidine-40 in ribonuclease T1 catalysis: three-dimensionalstructures of the partially active His40Lys mutant., Zegers I, Verhelst P, Choe HW, Steyaert J, Heinemann U, Saenger W, Wyns L, Biochemistry. 1992 Nov 24;31(46):11317-25. PMID:1445870
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