title: Outer membrane proteins of Methylococcus capsulatus (Bath).
abstract: Membranes obtained from whole-cell lysates of Methylococcus capsulatus (Bath) were separated by Triton X-100 extraction. The resulting insoluble fraction was enriched in outer membranes as assessed by electron microscopy and by the content of beta-hydroxy palmitic acid and particulate methane monooxygenase. Major proteins with molecular masses of approximately 27, 40, 46, 59, and 66 kDa were detected by SDS-PAGE of the Triton-X-100-insoluble membranes. MopA, MopB, MopC, MopD, and MopE (Methylococcus outer membrane protein) are proposed to designate these proteins. Several of the Mop proteins exhibited heat-modifiable properties in SDS-PAGE and were influenced by the presence of 2-mercaptoethanol in the sample buffer. The 46- and 59-kDa bands migrated as a single high-molecular-mass 95-kDa oligomer under mild denaturing conditions. When reconstituted into black lipid membranes, this oligomer was shown to serve as a channel with an estimated single-channel conductance of 1.4 nS in 1 M KCl.
authors.affiliation: Department of Molecular Biology, University of Bergen, Bergen High Technology Centre, N-5020 Bergen, Norway. anne.fjellbirkeland@pki.uib.no
authors.forename: A
authors.initials: A
authors.lastname: Fjellbirkeland
authors.forename: H
authors.initials: H
authors.lastname: Kleivdal
authors.forename: C
authors.initials: C
authors.lastname: Joergensen
authors.forename: H
authors.initials: H
authors.lastname: Thestrup
authors.forename: H B
authors.initials: HB
authors.lastname: Jensen
mesh_terms: D000595:Amino Acid Sequence; D001425:Bacterial Outer Membrane Proteins / Q000737:chemistry* / Q000187:drug effects; D002458:Cell Fractionation; D002462:Cell Membrane / Q000201:enzymology / Q000648:ultrastructure; D006358:Hot Temperature; D007473:Ion Channels; D008623:Mercaptoethanol / Q000494:pharmacology; D008772:Methylococcaceae / Q000737:chemistry* / Q000201:enzymology / Q000648:ultrastructure; D008969:Molecular Sequence Data; D010105:Oxygenases / Q000032:analysis; D010169:Palmitic Acids / Q000032:analysis; D010457:Peptidoglycan / Q000032:analysis; D017421:Sequence Analysis; D017386:Sequence Homology, Amino Acid
chemical_list: D001425:Bacterial Outer Membrane Proteins; D007473:Ion Channels; D010169:Palmitic Acids; D010457:Peptidoglycan; C108229:3-hydroxypalmitic acid; D008623:Mercaptoethanol; D010105:Oxygenases; C021555:methane monooxygenase