1loy
From Proteopedia
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| , resolution 1.55Å | |||||||
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| Ligands: | , | ||||||
| Activity: | Ribonuclease T(1), with EC number 3.1.27.3 | ||||||
| Related: | 1RGA, 1RLS, 1LOV, 1LOW
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| Resources: | FirstGlance, OCA, PDBsum, RCSB | ||||||
| Coordinates: | save as pdb, mmCIF, xml | ||||||
X-ray structure of the H40A/E58A mutant of Ribonuclease T1 complexed with 3'-guanosine monophosphate
Overview
Ribonucleases (RNases) catalyze the cleavage of the phosphodiester bond in RNA up to 10(15)-fold, as compared with the uncatalyzed reaction. High resolution crystal structures of these enzymes in complex with 3'-mononucleotide substrates demonstrate the accommodation of the nucleophilic 2'-OH group in a binding pocket comprising the catalytic base (glutamate or histidine) and a charged hydrogen bond donor (lysine or histidine). Ab initio quantum chemical calculations performed on such Michaelis complexes of the mammalian RNase A (EC ) and the microbial RNase T(1) (EC ) show negative charge build up on the 2'-oxygen upon substrate binding. The increased nucleophilicity results from stronger hydrogen bonding to the catalytic base, which is mediated by a hydrogen bond from the charged donor. This hitherto unrecognized catalytic dyad in ribonucleases constitutes a general mechanism for nucleophile activation in both enzymic and RNA-catalyzed phosphoryl transfer reactions.
About this Structure
1LOY is a Single protein structure of sequence from Aspergillus oryzae. Full crystallographic information is available from OCA.
Reference
A nucleophile activation dyad in ribonucleases. A combined X-ray crystallographic/ab initio quantum chemical study., Mignon P, Steyaert J, Loris R, Geerlings P, Loverix S, J Biol Chem. 2002 Sep 27;277(39):36770-4. Epub 2002 Jul 16. PMID:12122018
Page seeded by OCA on Sun Mar 30 22:05:31 2008
