On the mechanism of resistance to channel-forming colicins (PacB) and tellurite, encoded by plasmid Mip233 (IncHI3)

• Published in: FEMS microbiology letters 2000-11, Vol.192 (2), p.257-261
• Main Authors: Alonso, Guillermina, Gomes, Carlos, González, Carmen, Rodríguez Lemoine, Vidal
• Format: Article
• Language: English
• Subjects: Amino Acid Sequence; Bacteriology; Base Sequence; Binding Sites; Biological and medical sciences; Blotting, Northern; Colicins; Colicins - metabolism; Colicins - pharmacology; CysK; Deoxyribonucleic acid; DNA; Drug Resistance, Microbial - genetics; E coli; Ecological niches; Enzymes; Escherichia coli; Escherichia coli - drug effects; Escherichia coli - genetics; Escherichia coli - metabolism; Fundamental and applied biological sciences. Psychology; Genetics; Homology; IncH plasmid; Incompatibility; Microbiology; Molecular Sequence Data; Nucleotide sequence; PacB; PacB protein; Peptides - genetics; Peptides - metabolism; Phenotypes; Physiological effects; plasmid Mip233; Plasmids; Plasmids - biosynthesis; Plasmids - genetics; Polyacrylamide; Potassium tellurite; Reductase; Reductases; Ribosomes - genetics; Ribosomes - metabolism; RNA, Bacterial - genetics; RNA, Messenger - analysis; Sulfhydrylase; Tellurite; Tellurium - metabolism; Tellurium - pharmacology; Tellurium dioxide; Transcription; Transcription, Genetic
• ISSN: 0378-1097; 1574-6968
• DOI: 10.1111/j.1574-6968.2000.tb09391.x

Abstract Plasmids of the H incompatibility complex confer protection against all known channel-forming colicins (PacB character) and resistance to potassium tellurite (Ter) to Escherichia coli strains. A DNA clone (2.2 kbp) from plasmid Mip233 (IncHI3) expressing PacB-Ter phenotypes was studied. DNA sequence analysis revealed a high degree of homology with the enzyme O-acetylserine sulfhydrylase. Size of the PacB-Ter transcript was estimated as 1200 bases. A single polypeptide was found on SDS–polyacrylamide gel with a molecular mass estimated of 34 kDa. The effect of channel-forming colicins and tellurite was analyzed at physiological and transcriptional levels. Results suggest that the pacB gene product could be a reductase-like enzyme. It is also suggested that presence of the PacB character among H plasmid confers selective advantage on cells sharing an ecological niche.