title: Major outer membrane proteins in moderately halophilic eubacteria of genera Chromohalobacter and Halomonas.
abstract: Outer and inner membrane fractions of Chromohalobacter marismortui and Halomonas elongata were isolated by differential detergent solubilization, and profiles of membrane proteins, especially major outer membrane proteins, were analyzed. These type strains possessed one extremely abundant outer membrane protein which showed similarity in amino-terminal amino acid sequence with the outer membrane porin proteins in other Gram-negative bacteria. Three halophilic eubacterial strains isolated from saline environments were also characterized. Strains 160 and 43 were found to be Chromohalobacter spp. and strain 40 to be a Halomonas sp. by sequence analysis of their 16 S ribosomal RNA genes. Extremely abundant porin proteins with an apparent molecular mass of 49 kDa were found in Chromohalobacter sp.160 and Halomonas sp. 40, but no major outer membrane protein was detected in Chromohalobacter sp. 43, suggesting strain 43 was most likely a naturally defective porin mutant. Porin proteins from Chromohalobacter spp. and Halomonas spp. showed the same migration on SDS-polyacrylamide gel electrophoresis with or without heat-treatment, indicating that these porin proteins did not form a SDS-resistant trimeric structure, which was detected in most of the Gram-negative bacterial porin proteins.
authors.affiliation: Laboratory of Applied and Molecular Microbiology, Faculty of Agriculture, Kagoshima University, 1-21-24 Korimoto, Kagoshima 890-0065, Japan.
authors.forename: Hiroko
authors.initials: H
authors.lastname: Tokunaga
authors.forename: Kenjiro
authors.initials: K
authors.lastname: Mitsuo
authors.forename: Masahiro
authors.initials: M
authors.lastname: Kamekura
authors.forename: Masao
authors.initials: M
authors.lastname: Tokunaga
mesh_terms: D000595:Amino Acid Sequence; D001425:Bacterial Outer Membrane Proteins / Q000737:chemistry / Q000302:isolation & purification*; D004269:DNA, Bacterial / Q000737:chemistry / Q000302:isolation & purification; D004275:DNA, Ribosomal / Q000737:chemistry / Q000302:isolation & purification; D004591:Electrophoresis, Polyacrylamide Gel; D020459:Genes, rRNA; D044129:Halomonadaceae / Q000737:chemistry* / Q000302:isolation & purification; D020632:Halomonas / Q000737:chemistry* / Q000302:isolation & purification; D008969:Molecular Sequence Data; D008970:Molecular Weight; D009154:Mutation; D010802:Phylogeny; D018272:Porins / Q000737:chemistry / Q000235:genetics / Q000302:isolation & purification; D012336:RNA, Ribosomal, 16S / Q000235:genetics; D016415:Sequence Alignment; D017422:Sequence Analysis, DNA; D017386:Sequence Homology, Amino Acid; D012689:Sequence Homology, Nucleic Acid
chemical_list: D001425:Bacterial Outer Membrane Proteins; D004269:DNA, Bacterial; D004275:DNA, Ribosomal; D018272:Porins; D012336:RNA, Ribosomal, 16S