The role of methionine transport-defective mutations in resistance to methionine sulphoximine in Salmonella typhimurium

✍ Scribed by Betteridge, P. R. ;Ayling, P. D.

• Publisher: Springer
• Year: 1975
• Tongue: English
• Weight: 712 KB
• Volume: 138
• Category: Article
• ISSN: 0026-8925
• DOI: 10.1007/bf00268826

✦ Synopsis

Two classes of Salmonella typhimurium mutants resistant to inhibitory methionine analogues and defective in methionine transport have been examined. A mutant of the first class, resistant to alpha-methylmethionine, was shown by conjugation analysis to possess a single mutation in the metP gene which specifies a methionine transport system. Mutants of the second class, resistant to alpha-methylmethionine and methionine sulphoximine, possess two mutations. One is in the metP gene, which accounts for resistance to alpha-methylmethionine, and the other is in a gene designated glnP which results in reduced L-glutamine transport. Both of these mutations are required for resistance to methionine sulphoximine. A transduction analysis of three metP mutations was performed, based on the fact that they prevent growth of methionine-requiring strains on D-methionine. Two of the mutants are closely linked and therefore probably in the same gene, whereas the third mutant might be in a different gene.