1ch0
RNASE T1 VARIANT WITH ALTERED GUANINE BINDING SEGMENTRNASE T1 VARIANT WITH ALTERED GUANINE BINDING SEGMENT
Structural highlights
FunctionEvolutionary Conservation Check, as determined by ConSurfDB. You may read the explanation of the method and the full data available from ConSurf. Publication Abstract from PubMedThe ribonuclease T1 variant 9/5 with a guanine recognition segment, altered from the wild-type amino acid sequence 41-KYNNYE-46 to 41-EFRNWQ-46, has been cocrystallised with the specific inhibitor 2'-GMP. The crystal structure has been refined to a crystallographic R factor of 0.198 at 2.3 A resolution. Despite a size reduction of the binding pocket, pushing the inhibitor outside by 1 A, 2'-GMP is fixed to the primary recognition site due to increased aromatic stacking interactions. The phosphate group of 2'-GMP is located about 4.2 A apart from its position in wild-type ribonuclease T1-2'-GMP complexes, allowing a Ca(2+), coordinating this phosphate group, to enter the binding pocket. The crystallographic data can be aligned with the kinetic characterisation of the variant, showing a reduction of both, guanine affinity and turnover rate. The presence of Ca(2+) was shown to inhibit variant 9/5 and wild-type enzyme to nearly the same extent. Structural analysis of an RNase T1 variant with an altered guanine binding segment.,Hoschler K, Hoier H, Hubner B, Saenger W, Orth P, Hahn U J Mol Biol. 1999 Dec 17;294(5):1231-8. PMID:10600381[1] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. See AlsoReferences
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