2aae

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spinqualitylabelsall models 2aae, resolution 1.8Å Show:Asymmetric Unit Biological Assembly Drag the structure with the mouse to rotate   Export Animated Image

THE ROLE OF HISTIDINE-40 IN RIBONUCLEASE T1 CATALYSIS: THREE-DIMENSIONAL STRUCTURES OF THE PARTIALLY ACTIVE HIS40LYS 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

2AAE is a Single protein structure of sequence from Aspergillus oryzae with CA and PO4 as ligands. Active as Ribonuclease T(1), with EC number 3.1.27.3 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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