Role of flagellins from A and B loci in flagella formation of Halobacterium salinarum

Haloarchaeal flagella are composed of a number of distinct flagellin protei ns, specified by genes in two separate operons (A and B). The roles of thes e flagellins were assessed by studying mutants of H. salinarum with inserti ons in either the A or the B operon, Cells of the flgA(-) mutant produced a bnormally short, curved flagella that were distributed all over the cell su rface. The flgA2(-) strain produced straight flagella, mainly found at the poles. The flgB(-) mutant had flagella of the same size and spiral shape as wild-type cells, but these cells also showed unusual outgrowths, which app eared to be sacs filled with basal body-like structures. In broth cultures of this mutant, the medium accumulated flagella with basal body-like struct ures at their ends.