1y42

From Proteopedia

Revision as of 04:25, 21 November 2007

Crystal structure of a C-terminally truncated CYT-18 protein

Overview

We determined a 1.95 A X-ray crystal structure of a C-terminally truncated, Neurospora crassa mitochondrial tyrosyl-tRNA synthetase (CYT-18 protein), that functions in splicing group I introns. CYT-18's nucleotide binding, fold and intermediate alpha-helical domains superimpose on those of, bacterial TyrRSs, except for an N-terminal extension and two small, insertions not found in nonsplicing bacterial enzymes. These additions, surround the cyt-18-1 mutation site and are sites of suppressor mutations, that restore splicing, but not synthetase activity. Highly constrained, models based on directed hydroxyl radical cleavage assays show that the, group I intron binds at a site formed in part by the three additions on, the nucleotide binding fold surface opposite that which binds tRNATyr. Our, results show how essential proteins can progressively evolve new, functions.

About this Structure

1Y42 is a Single protein structure of sequence from Neurospora crassa with TYR as ligand. Active as Tyrosine--tRNA ligase, with EC number 6.1.1.1 Full crystallographic information is available from OCA.

Reference

A tyrosyl-tRNA synthetase adapted to function in group I intron splicing by acquiring a new RNA binding surface., Paukstelis PJ, Coon R, Madabusi L, Nowakowski J, Monzingo A, Robertus J, Lambowitz AM, Mol Cell. 2005 Feb 4;17(3):417-28. PMID:15694342

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