1ch0
From Proteopedia
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| , resolution 2.3Å | |||||||
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| Ligands: | , , | ||||||
| Activity: | Ribonuclease T(1), with EC number 3.1.27.3 | ||||||
| Resources: | FirstGlance, OCA, PDBsum, RCSB | ||||||
| Coordinates: | save as pdb, mmCIF, xml | ||||||
RNASE T1 VARIANT WITH ALTERED GUANINE BINDING SEGMENT
Overview
The 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.
About this Structure
1CH0 is a Single protein structure of sequence from Aspergillus oryzae. Full crystallographic information is available from OCA.
Reference
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
Page seeded by OCA on Sun Mar 30 19:21:31 2008
