Molecular cloning of a gene encoding a 23-kDa outer membrane polypeptide from the cryptic plasmid ofSalmonella typhimurium

Abstract

A cosmid bank of the DNA of Salmonella typhimurium LT2 was prepared in Escherichia coli K12, and probed with radiolabelled cryptic plasmid from the same Salmonella strain. 2 of the 7 clones thus detected expressed an obvious new outer membrane protein of 23 kDa. The gene encoding the polypeptide was subcloned, in a 6.6‐kb ClaI fragment, from one of the cosmids into pBR322. The clone was mapped with restriction enzymes. The gene location and the direction of transcription were defined with the aid of transposon Tn1725 insertions. The gene product was detected in minicells. The protein was partially peptidoglycan‐associated in E. coli.

The outer membrane permeability mutation of the virulence-associated plasmid of Salmonella typhimurium is located in a traT-like gene

“…Only two proteins specified by the virulence-associated plasmid of S. typhimurium have been identified previously; a M r 23000 outer membrane protein and an M r 11 000 serum resistanceassociated protein [30,31]. Only two proteins specified by the virulence-associated plasmid of S. typhimurium have been identified previously; a M r 23000 outer membrane protein and an M r 11 000 serum resistanceassociated protein [30,31].…”