A mutational hot-spot in the hisM gene of the histidine transport operon in Salmonella typhimurium is due to deletion of repeated sequences and results in an altered specificity of transport
✍ Scribed by Payne, Gillian M. ;Spudich, Elena N. ;Ferro-Luzzi Ames, Giovanna
- Publisher
- Springer
- Year
- 1985
- Tongue
- English
- Weight
- 404 KB
- Volume
- 200
- Category
- Article
- ISSN
- 0026-8925
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✦ Synopsis
Duplicated sequences within hisM, a gene coding for a membrane-bound component of histidine transport, result in frequent deletions which, being in frame, allow production of an altered protein with apparent changed specificity of transport. While the wild-type transport system does not transport L-histidinol but does transport Lhistidine and several of its analogs, the hisM deletion mutants do not transport the latter compounds but do transport r-histidinol. These results are interpreted as supporting the hypothesis (Ames and Higgins 1983) that transport through periplasmic systems involves binding of the substrate by the cytoplasmic membrane-bound components.