Archaeal motility occurs by the rotation of flagella that show similarity to bacterial type IV pili, including the multiflagellin nature of the flagellar filament, N-terminal sequence similarities, as well as the presence of homologous proteins in the two systems [2,3]. Similar to type IV pilins, archaeal flagellins are initially synthesised with a short leader peptide that is cleaved by a membrane-located peptidase [3,4]. The enzyme responsible for the removal of the this leader peptide is FlaK [4]. Archaeal flagella are composed of a number of distinct flagellin proteins, specified by genes in two separate operons (A and B) [6].

1: Halobacterial flagellins are encoded by a multigene family. Characterization of five flagellin genes. Gerl L, Sumper M; J Biol Chem 1988;263:13246-13251. PMID:3417656

2: Archaeal flagella, bacterial flagella and type IV pili: a comparison of genes and posttranslational modifications. Ng SY, Chaban B, Jarrell KF; J Mol Microbiol Biotechnol. 2006;11:167-191. PMID:16983194

3: The archaeal flagellum: a different kind of prokaryotic motility structure. Thomas NA, Bardy SL, Jarrell KF; FEMS Microbiol Rev 2001;25:147-174. PMID:11250034

4: Recent advances in the structure and assembly of the archaeal flagellum. Bardy SL, Ng SY, Jarrell KF; J Mol Microbiol Biotechnol. 2004;7:41-51. PMID:15170402

5: Cleavage of preflagellins by an aspartic acid signal peptidase is essential for flagellation in the archaeon Methanococcus voltae. Bardy SL, Jarrell KF; Mol Microbiol. 2003;50:1339-1347. PMID:14622420

6: Role of flagellins from A and B loci in flagella formation of Halobacterium salinarum. Tarasov VY, Pyatibratov MG, Tang SL, Dyall-Smith M, Fedorov OV; Mol Microbiol. 2000;35:69-78. PMID:10632878