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Microbiology. 2002 Mar;148(Pt 3):657-65.

Mutagenesis of conserved tryptophan residues within the receptor-binding domain of intimin: influence on binding activity and virulence.

Author information

1
Centre for Molecular Microbiology and Infection and Centre for Structural Biology, Department of Biological Sciences, Imperial College of Science, Technology and Medicine, London SW7 2AZ, UK.

Abstract

Intimate bacterial adhesion to intestinal epithelium is a pathogenic mechanism shared by several human and animal enteric pathogens, including enteropathogenic and enterohaemorrhagic Escherichia coli and Citrobacter rodentium. The proteins directly involved in this process are the outer-membrane adhesion molecule intimin and the translocated intimin receptor, Tir. The receptor-binding activity of intimin resides within the carboxy terminus 280 aa (Int280) of the polypeptide. Four tryptophan residues, W117/776, W136/795, W222/881 and W240/899, are conserved within different Int280 molecules that otherwise show considerable sequence variation. In this study the influence of site-directed mutagenesis of each of the four tryptophan residues on intimin-Tir interactions and on intimin-mediated intimate attachment was determined. The mutant intimins were also studied using a variety of in vitro and in vivo infection models. The results show that all the substitutions modulated intimin activity, although some mutations had more profound effects than others.

PMID:
11882699
DOI:
10.1099/00221287-148-3-657
[Indexed for MEDLINE]

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