title: Brucella Omp2a and Omp2b porins: single channel measurements and topology prediction.
abstract: Brucella usually carry two highly homologous genes (omp2a and omp2b) for porin-like proteins. In several B. abortus biovars the omp2a gene has a large deletion compared to other Brucella omp2's. In this study we have measured Omp2 pore activity in planar bilayers. Omp2b exhibits well-defined trimeric channel activity whilst Omp2a forms monomeric pores of variable size which are smaller than Omp2b. No sequence homology exists between Omp2 and porins of known structure, so hydrophobic moment analysis has been used to model their membrane topology. From this it appears likely that the deletion removes the crucial L3 internal loop.
authors.affiliation: School of Biological Sciences, University of East Anglia, Norfolk, UK.
authors.forename: H
authors.initials: H
authors.lastname: Mobasheri
authors.forename: T A
authors.initials: TA
authors.lastname: Ficht
authors.forename: H
authors.initials: H
authors.lastname: Marquis
authors.forename: E J
authors.initials: EJ
authors.lastname: Lea
authors.forename: J H
authors.initials: JH
authors.lastname: Lakey
mesh_terms: D000595:Amino Acid Sequence; D001426:Bacterial Proteins; D002003:Brucella abortus / Q000235:genetics* / Q000378:metabolism*; D004926:Escherichia coli / Q000235:genetics; D005798:Genes, Bacterial; D007473:Ion Channels / Q000737:chemistry / Q000378:metabolism; D008051:Lipid Bilayers / Q000737:chemistry; D008564:Membrane Potentials; D008969:Molecular Sequence Data; D018272:Porins / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism*; D017433:Protein Structure, Secondary; D017384:Sequence Deletion; D017386:Sequence Homology, Amino Acid
chemical_list: D001426:Bacterial Proteins; D007473:Ion Channels; D008051:Lipid Bilayers; C096735:Omp2a protein, Brucella; C096736:Omp2b protein, Brucella; D018272:Porins