1: J Bacteriol. 2006 Dec 15; [Epub ahead of print]

Loss of a universal tRNA feature.

Wang C, Sobral BW, Williams KP.

Virginia Bioinformatics Institute, Virginia Polytechnic Institute and State
University, Blacksburg VA 24061.

tRNA(His) has always hitherto been found with one of the most distinctive of
tRNA features, an extra 5 nucleotide that is usually a guanylate. tRNA(His)
genes in a disjoint alphaproteobacterial group comprising the Rhizobiales,
Rhodobacterales, Caulobacterales, Parvularculales and Pelagibacter generally
fail to encode this extra guanylate, unlike those of other alphaproteobacteria
and bacteria in general. Rather than adding an extra 5 guanylate
posttranscriptionally as eukaryotes do, evidence is presented that two of these
species, Sinorhizobium meliloti and Caulobacter crescentus, simply lack any
extra nucleotide on tRNA(His). This loss correlates with changes at the 3 end
sequence of tRNA(His) and at many sites in histidyl-tRNA synthetase that might
be expected to affect tRNA(His) recognition, in the flipping loop, the insertion
domain, the anticodon-binding domain, and in the motif 2 loop. The altered tRNA
charging system may have affected other tRNA charging systems in these bacteria;
for example, a site in tRNA(Glu) sequences was found to covary with tRNA(His)
among alphaproteobacteria.

PMID: 17172343 [PubMed - as supplied by publisher]

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