Amino acid sequences of pilins from serologically distinct strains of Bacteroides nodosus

CSIRO, Division of Protein Chemistry, Parkville, Australia.
Journal of Protein Chemistry 05/1988; 7(2):157-64. DOI: 10.1007/BF01025245
Source: PubMed


Amino acid sequences of pilin from a strain of Bacteroides nodosus from serogroup B (234) and serogroup C (217) were determined. The amino-terminal N-methylphenlalanine residue of both proteins was followed by a hydrophobic sequence of 30 residues closely related to the N-terminal sequence of other pili having an amino-terminal residue of N-methylphenylalanine. These data lend support to the hypothesis that in pilins of this type, the amino-terminal sequence functions as a transport signal necessary for pilin to reach its external environment, as well as promoting intersubunit interactions for maintenance of the structural integrity of the pilus. Two hydrophilic hypervariable regions can be discerned across the pilin sequences, indicating possible locations of antigenic domains.

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    ABSTRACT: Sequences of pilin genes from four strains of serogroup B of the ovine pathogen Bacteroides nodosus have been determined. These sequences permit comparisons of amino acid sequence between pilins from different subtypes (B1, B2, B3, B4) of the B serogroup and assessment of intraserogroup variation. Pili of B. nodosus strains 234 (B1) and 183 (B2) were produced by Pseudomonas aeruginosa harboring a plasmid-borne B. nodosus pilin gene, and these pili were used in sheep vaccination trials. Pili from strain 183 (B2) were found to be a senior antigen to pili from strains of other B subtypes, providing protection against footrot infection caused by strains of the other B subtypes. Pili of this strain are therefore the most suitable candidate for inclusion in a pilus-based vaccine. Pili of strain 234 from subtype B1, the reference strain of the B serogroup, provided poor protection against infection with other subtypes.
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