Bacterial SLH domain proteins are non-covalently anchored to the cell surface via a conserved mechanism involving wall polysaccharide pyruvylation.
Several bacterial proteins are non-covalently anchored to the cell surface via an S-layer homology (SLH) domain. Previous studies have suggested that this cell surface display mechanism involves a non-covalent interaction between the SLH domain and peptidoglycan-associated polymers. Here we report the characterization of a two-gene operon, csaAB, for cell surface anchoring, in Bacillus anthracis. Its distal open reading frame (csaB) is required for the retention of SLH-containing proteins on the cell wall. Biochemical analysis of cell wall components showed that CsaB was involved in the addition of a pyruvyl group to a peptidoglycan-associated polysaccharide fraction, and that this modification was necessary for binding of the SLH domain. The csaAB operon is present in several bacterial species that synthesize SLH-containing proteins. This observation and the presence of pyruvate in the cell wall of the corresponding bacteria suggest that the mechanism described in this study is widespread among bacteria.
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Toxines et Pathogénie Bactériennes (URA 1858, CNRS), Institut Pasteur, 28 rue du Dr Roux, 75724 Paris, cédex 15, France.
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D019880:Aldehyde-Ketone Transferases / Q000378:metabolism*; D001408:Bacillus anthracis / Q000201:enzymology / Q000235:genetics / Q000378:metabolism*; D001426:Bacterial Proteins / Q000378:metabolism*; D001483:Base Sequence; D002247:Carbon Isotopes; D002473:Cell Wall / Q000201:enzymology*; D017931:DNA Primers; D009154:Mutation; D019906:Nuclear Magnetic Resonance, Biomolecular; D011522:Protons
D001426:Bacterial Proteins; D002247:Carbon Isotopes; D017931:DNA Primers; D011522:Protons; D019880:Aldehyde-Ketone Transferases; C050676:polysaccharide pyruvyltransferase