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1pud
From Proteopedia
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| , resolution 1.85Å | |||||||
|---|---|---|---|---|---|---|---|
| Ligands: | |||||||
| Gene: | TGT (Zymomonas mobilis) | ||||||
| Activity: | Queuine tRNA-ribosyltransferase, with EC number 2.4.2.29 | ||||||
| Coordinates: | save as pdb, mmCIF, xml | ||||||
TRNA-GUANINE TRANSGLYCOSYLASE
Overview
tRNA-guanine transglycosylases (TGT) are enzymes involved in the modification of the anticodon of tRNAs specific for Asn, Asp, His and Tyr, leading to the replacement of guanine-34 at the wobble position by the hypermodified base queuine. In prokaryotes TGT catalyzes the exchange of guanine-34 with the queuine (.)precursor 7-aminomethyl-7-deazaguanine (preQ1). The crystal structure of TGT from Zymomonas mobilis was solved by multiple isomorphous replacement and refined to a crystallographic R-factor of 19% at 1.85 angstrom resolution. The structure consists of an irregular (beta/alpha)8-barrel with a tightly attached C-terminal zinc-containing subdomain. The packing of the subdomain against the barrel is mediated by an alpha-helix, located close to the C-terminus, which displaces the eighth helix of the barrel. The structure of TGT in complex with preQ1 suggests a binding mode for tRNA where the phosphate backbone interacts with the zinc subdomain and the U33G34U35 sequence is recognized by the barrel. This model for tRNA binding is consistent with a base exchange mechanism involving a covalent tRNA-enzyme intermediate. This structure is the first example of a (beta/alpha)-barrel protein interacting specifically with a nucleic acid.
About this Structure
1PUD is a Single protein structure of sequence from Zymomonas mobilis. Full crystallographic information is available from OCA.
Reference
Crystal structure of tRNA-guanine transglycosylase: RNA modification by base exchange., Romier C, Reuter K, Suck D, Ficner R, EMBO J. 1996 Jun 3;15(11):2850-7. PMID:8654383
Page seeded by OCA on Thu Mar 20 13:29:07 2008
