Nucleotide sequence analysis of the structural genes for Shiga-like toxin I encoded by bacteriophage 933J from Escherichia coli

Abstract

A nucleotide sequence analysis was performed on the Shiga-like toxin I genes previously cloned from the Escherichia coli bacteriophage 933J. Two structural genes designated slt-I A and slt-I B were found to be oriented on a single transcriptional unit with slt-I A preceding slt-I B. A 12 base pair gap separated the in-phase open reading frames of slt-I A and slt-I B. Putative ribosome binding sites were identified 5' to both the slt-I A and slt-I B genes. Translation of the SLT-I nucleotide sequence revealed that both the A and B subunits were synthesized with signal peptides. The molecular weight calculated for the mature A subunit was 32,211 while the molecular weight of the mature B subunit was 7690.