RESUMO
Many Archaea use rotation of helical flagellar filaments for swimming motility. We isolated and characterized the flagellar filaments of Haloarcula marismortui, an archaeal species previously considered to be nonmotile. Two Haloarcula marismortui phenotypes were discriminated--their filaments are composed predominantly of either FlaB or FlaA2 flagellin, and the corresponding genes are located on different replicons. FlaB and FlaA2 filaments differ in antigenicity and thermostability. FlaA2 filaments are distinctly thicker (20-22 nm) than FlaB filaments (16-18 nm). The observed filaments are nearly twice as thick as those of other characterized euryarchaeal filaments. The results suggest that the helicity of Haloarcula marismortui filaments is provided by a mechanism different from that in the related haloarchaeon Halobacterium salinarum, where 2 different flagellin molecules present in comparable quantities are required to form a helical filament.
Assuntos
Proteínas Arqueais/metabolismo , Cloretos/metabolismo , Flagelos/metabolismo , Flagelina/metabolismo , Haloarcula marismortui/metabolismo , Sequência de Aminoácidos , Proteínas Arqueais/química , Proteínas Arqueais/genética , Flagelos/química , Flagelos/genética , Flagelina/química , Flagelina/genética , Haloarcula marismortui/química , Haloarcula marismortui/genética , Dados de Sequência Molecular , Alinhamento de SequênciaRESUMO
We examine distribution of flagellins along multicomponent flagellar filaments (FF) and protofilaments (PF) of the haloalkaliphilic archaeon Natrialba magadii using immunogold electron microscopy. A high specific polyclonal antibody raised to one of the flagellin types bound homogeneously to the undissociated FF along the full length. At the same time both uniformly labelled and completely unlabelled PF, outwardly indistinguishable one from another, were observed.
