Characterisation of Potential Antimicrobial Targets in Bacillus ssp. I. Aminotransferases and Methionine Regeneration in Bacillus Subtilis.

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Authors
  1. Berger, B.J.
  2. Knodel, M.H.
Corporate Authors
Defence R&D Canada - Suffield, Ralston ALTA (CAN)
Abstract
The aminotransferases involved in the final step of methionine recycling from methylthioadenosine have been examined in the gram-positive bacterium Bacillus subtilis. Homogenates of this bacterium were able to convert ketomethiobutyrate to methionine, utilising leucine, isoleucine, valine, phenylalanine, tyrosine, and alanine as preferred amino donors. Unlike other organisms examined to date in this context, B. subtilis was found to contain no aspartate aminotransferase or tyrosine aminotransferase sequences with structural homology to subfamily Ia aminotransferases. Instead, in B. subtilis, the six putative homologues of aspartate aminotransferase were found to be members of the If subfamily. Five of these six sequences were cloned and expressed, with only the ykrV gene product capable of producing methionine from ketomethiobutyrate. However, this enzyme only catalysed the reaction using glutamine as an amino donor. Two putative branched-chain amino acid aminotransferases from family III were also cloned and expressed, and both were found to produce methionine from ketomethiobutyrate using branched-chain and aromatic amino acids. Of these two enzymes, the ybgE gene product was the most active and had kinetic constants consistent with it being the enzyme responsible for the majority of methionine regeneration in this organism. TRUNCATED

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Keywords
Aminotransferases;Methionine recycling;Biological Warfare Agents;Canaline;Inhibition
Report Number
DRDC-SUFFIELD-TR-2002-048 — Technical Report
Date of publication
01 Jul 2002
Number of Pages
44
DSTKIM No
CA021217
CANDIS No
517937
Format(s):
Hardcopy;Document Image stored on Optical Disk

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