2AAD

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

Summary for 2AAD

• Entry DOI: 10.2210/pdb2aad/pdb
• Descriptor: RIBONUCLEASE T1 ISOZYME, CALCIUM ION, GUANOSINE-2'-MONOPHOSPHATE, ... (4 entities in total)
• Functional Keywords: hydrolase(endoribonuclease)
• Biological source: Aspergillus oryzae
• Total number of polymer chains: 2
• Total formula weight: 22978.05

Authors

Zegers, I.,Verhelst, P.,Choe, C.W.,Steyaert, J.,Heinemann, U.,Wyns, L.,Saenger, W. (deposition date: 1992-09-15, release date: 1994-01-31, Last modification date: 2024-11-06)

Primary citation

Zegers, I.,Verhelst, P.,Choe, H.W.,Steyaert, J.,Heinemann, U.,Saenger, W.,Wyns, L.
Role of histidine-40 in ribonuclease T1 catalysis: three-dimensionalstructures of the partially active His40Lys mutant.
Biochemistry, 31:11317-11325, 1992

PubMed Abstract: 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)

PubMed: 1445870
DOI: 10.1021/bi00161a009

Experimental method

X-RAY DIFFRACTION (2 Å)