Segment IV of a Salmonella flagellin gene specifies flagellar antigen epitopes

Abstract

Each of the two mutants isolated from a fliC (= hag, flagellin-deficient) Escherichia coli strain made motile by a plasmid carrying the fliC gene of Salmonella muenchen by selection for motility in the presence of anti-d (Salmonella flagellar antigen) serum had both lost and gained one or more subfactors of the wild-type antigen. In one mutant codon 246 was GAC (alanine) instead of GCC (asparagine); the other had a deletion of 105 base pairs, explicable by a 10bp direct repeat, starting at bases 782 and 887. The in vitro removal of a 48bp EcoRV(631)/EcoRV(679) fragment produced plasmid pLS408, which was found to lack a subfactor of wild-type antigen d but able to confer motility on flagellin-negative Salmonella sp. (and used for insertion of epitope-specifying oligonucleotides at its EcoRV site). Immunoblotting with absorbed and unabsorbed sera from rabbits immunized with E. coli with wild-type or mutated antigen d showed that the fusion proteins specified by lambda gt11 with the N-terminal part of gene lacZ joined to a restriction fragment coding for residues 145-391 of flagellin gave the same pattern of parent-specific and mutant-specific reactions as the flagellate bacteria. Four out of five similarly selected mutants had the same 105 bp deletion as the first-isolated mutant; the fifth had a 72 bp deletion made possible by a 7-base pair direct repeat, starting at positions 649 and 721. All these changes in serological character without loss of function affected segment IV, specifying residues 182 to 308 of the total of 505, where there is little homology between different flagellar-antigen alleles.

The bvgAS locus negatively controls motility and synthesis of flagella in Bordetella bronchiseptica

“…There is no obvious correlation between flagellin type and the source of isolation, and we have not observed switching between isotypes within the same strain. 1 Flagellin molecules from diverse bacterial species are commonly observed to share amino acid sequence similarity at their amino and carboxy termini, whereas the central regions are often heterogeneous and contain specific antigenic epitopes (33,43). It is interesting that the first 31 residues of the B. bronchiseptica BB7865 flagellin are as related to the S. typhimurium sequence (80% identity) as the S. typhimunum flagellin is to that encoded by E. coli.…”

Flagellin from an Incompatible Strain of Pseudomonas avenae Induces a Resistance Response in Cultured Rice Cells

“…The central domain (D3) of adjacent subunits in a filament is not connected to each other. This D3 domain corresponds with the hypervariable region located on the surface of the flagellin filament, and there are several lines of evidence showing that the exposed D3 domain contains the major epitopes of H antigen (51)(52)(53)(54). The sequence analysis of P. avenae flagellin genes showed that all of the amino acid residues (14 amino acid residues) varying between the incompatible N1141 and the compatible H8301 strains are located in the D3 domains.…”

Multiplex PCR for Distinguishing the Most Common Phase-1 Flagellar Antigens of Salmonella spp

“…The amino-and carboxy-terminal sequences (regions I and II and region VIII, respectively) are conserved and are thought to be important for polymerization and transportation. The central region, which comprises regions IV, V, and VI, is highly variable in both sequence and length between flagellar antigen genes and is generally believed to determine the epitope of the H antigen (13,18).…”