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PDBsum entry 2aad
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Hydrolase(endoribonuclease)
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PDB id
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2aad
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Contents |
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* Residue conservation analysis
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References listed in PDB file
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Key reference
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Title
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Role of histidine-40 in ribonuclease t1 catalysis: three-Dimensionalstructures of the partially active his40lys mutant.
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Authors
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I.Zegers,
P.Verhelst,
H.W.Choe,
J.Steyaert,
U.Heinemann,
W.Saenger,
L.Wyns.
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Ref.
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Biochemistry, 1992,
31,
11317-11325.
[DOI no: ]
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PubMed id
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Abstract
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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)
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