FLAGELLIN GENES OF METHANOCOCCUS-VANNIELII - AMPLIFICATION BY THE POLYMERASE-CHAIN-REACTION, DEMONSTRATION OF SIGNAL PEPTIDES AND IDENTIFICATION OF MAJOR COMPONENTS OF THE FLAGELLAR FILAMENT

The highly conserved nature of the 5'-termini of all archaeal flagelli n genes was exploited by polymerase chain reaction (PCR) techniques to amplify the sequence of a portion of a flagellin gene family from the archaeon Methanococcus vannielii. Subsequent inverse PCR experiments generated fragments that permitted the sequencing of a total of three flagellin genes, which, by comparison with flagellin genes that have b een sequenced, from other archaea appear to be equivalent to flaB1, fl aB2, and flaB3 of M. voltae. Analysis of purified M. vannielii flagell ar filaments by sodium dodecyl sulfate polyacrylamide gel electrophore sis (SDS-PAGE) revealed two major flagellins (M-r = 30 800 and 28 600) , whose N-terminal sequences identified them as the products of the fl aB1 and flaB2 genes, respectively. The gene product of flaB3 could not be detected in flagellar filaments by SDS-PAGE. The protein sequence data, coupled with the DNA sequences, demonstrated that both FlaB1 and FlaB2 flagellins are translated with a 12-amino acid signal peptide w hich is absent from the mature protein incorporated into the flagellar filament. These data suggest that archaeal flagellin export differs s ignificantly from that of bacterial flagellins.