Evidence for two different gas vesicle proteins and genes in Halobacterium halobium.
Most halobacteria produce gas vesicles (GV). The well-characterized species Halobacterium halobium and some GV+ revertants of GV- mutants of H. halobium produce large amounts of GV which have a spindlelike shape. Most other GV+ revertants of H. halobium GV- mutants and other recently characterized halobacterial wild-type strains possess GV with a cylindrical form. The number of intact particles in the latter isolates is only 10 to 30% of that of H. halobium. Analysis of GV envelope proteins (GVPs) by electrophoresis on phenol-acetic acid-urea gels showed that the GVP of the highly efficient GV-producing strains migrated faster than the GVP of the low-GV-producing strains. The relative molecular mass of the GVP was estimated to be 19 kilodaltons (kDa) for high-producing strains (GVP-A) and 20 kDa for low-producing strains (GVP-B). Amino acid sequence analysis of the first 40 amino acids of the N-terminal parts of GVP-A and GVP-B indicated that the two proteins differed in two defined positions. GVP-B, in relation to GVP-A, had Gly-7 and Val-28 always replaced by Ser-7 and Ile-28, respectively. These data suggest that at least two different gvp genes exist in H. halobium NRL. This was directly demonstrated by hybridization experiments with gvp-specific DNA probes. A fragment of plasmid pHH1 and a chromosomal fragment of H. halobium hybridized to the probes. Only a chromosomal fragment hybridized to the same gyp probes when both chromosomal and plasmid DNAs from the low-GV-producing halobacterial wild-type strains SB3 and GN101 were examined. These findings support the assumption that GVP-A is expressed by a pHH1-associated gvp gene and GVP-B by a chromosomal gvp gene.
Surek
B
B
Institut für Genetik und Mikrobiologie, Universität Würzburg, Federal Republic of Germany.
Pillay
B
B
Rdest
U
U
Beyreuther
K
K
Goebel
W
W
D000595:Amino Acid Sequence; D019843:Archaeal Proteins; D001425:Bacterial Outer Membrane Proteins / Q000032:analysis* / Q000235:genetics; D001426:Bacterial Proteins / Q000032:analysis* / Q000235:genetics; D004269:DNA, Bacterial / Q000235:genetics; D004587:Electrophoresis, Agar Gel; D004591:Electrophoresis, Polyacrylamide Gel; D005798:Genes, Bacterial; D006217:Halobacterium / Q000737:chemistry / Q000235:genetics* / Q000648:ultrastructure; D008565:Membrane Proteins; D008854:Microscopy, Electron; D008969:Molecular Sequence Data; D009693:Nucleic Acid Hybridization; D011506:Proteins
D019843:Archaeal Proteins; D001425:Bacterial Outer Membrane Proteins; D001426:Bacterial Proteins; D004269:DNA, Bacterial; D008565:Membrane Proteins; D011506:Proteins; C038524:gas vesicle protein