title: Oligomerization mechanisms of an H-NS family protein, Pmr, encoded on the plasmid pCAR1 provide a molecular basis for functions of H-NS family members.
abstract: Enterobacterial H-NS-like proteins and Pseudomonas MvaT-like proteins share low homology at the amino acid sequence level, but both can function as xenogeneic silencers and are included in the H-NS family of proteins. H-NS family members have dimerization/oligomerization and DNA-binding domains connected by a flexible linker and form large nucleoprotein complexes using both domains. Pmr, an MvaT-like protein encoded on the IncP-7 carbazole-degradative plasmid pCAR1, is a key regulator of an interaction between pCAR1 and its host Pseudomonas putida KT2440. KT2440 has two transcribed genes that encode the MvaT-like proteins TurA and TurB. Our previous transcriptome analyses suggested that the functions of Pmr, TurA and TurB are non-equivalent, although the detailed underlying mechanisms remain unclear. In this study, we focused on the protein-protein interactions of Pmr, and assessed the homo-oligomerization capacity of various substituted and truncated Pmr derivatives by protein-protein cross-linking analysis. Six of the seven residues identified as important for homo-oligomerization in Pmr were located near the N-terminus, and the putative flexible linker or the region near that was not involved in homo-oligomerization, suggesting that Pmr homo-oligomerization is different from that of enterobacterial H-NS and that the functional mechanism differs between H-NS-like and MvaT-like proteins. In addition, we assessed homo- and hetero-oligomerization of Pmr by surface plasmon resonance analysis and found that the coupling ratio of TurB-Pmr oligomers is smaller than that of Pmr-Pmr or TurA-Pmr oligomers. These results raised the possibility that composition of the hetero-oligomers of Pmr, TurA, and TurB could explain why the different gene sets were affected by either pmr, turA, or turB disruption in our previous studies.
authors.affiliation: Biotechnology Research Center, The University of Tokyo, Tokyo, Japan.
authors.forename: Chiho
authors.initials: C
authors.lastname: Suzuki
authors.affiliation: Biotechnology Research Center, The University of Tokyo, Tokyo, Japan.
authors.forename: Kohei
authors.initials: K
authors.lastname: Kawazuma
authors.affiliation: Department of Applied Biological Chemistry, Graduate School of Agricultural and Life Sciences, The University of Tokyo, Tokyo, Japan.
authors.forename: Shoichiro
authors.initials: S
authors.lastname: Horita
authors.affiliation: Agricultural Bioinformatics Research Unit, Graduate School of Agricultural and Life Sciences, The University of Tokyo, Tokyo, Japan.
authors.forename: Tohru
authors.initials: T
authors.lastname: Terada
authors.affiliation: Department of Applied Biological Chemistry, Graduate School of Agricultural and Life Sciences, The University of Tokyo, Tokyo, Japan.
authors.forename: Masaru
authors.initials: M
authors.lastname: Tanokura
authors.affiliation: Biotechnology Research Center, The University of Tokyo, Tokyo, Japan.
authors.forename: Kazunori
authors.initials: K
authors.lastname: Okada
authors.affiliation: Biotechnology Research Center, The University of Tokyo, Tokyo, Japan.
authors.forename: Hisakazu
authors.initials: H
authors.lastname: Yamane
authors.affiliation: Biotechnology Research Center, The University of Tokyo, Tokyo, Japan; Agricultural Bioinformatics Research Unit, Graduate School of Agricultural and Life Sciences, The University of Tokyo, Tokyo, Japan.
authors.forename: Hideaki
authors.initials: H
authors.lastname: Nojiri
mesh_terms: D000595:Amino Acid Sequence; D001426:Bacterial Proteins / Q000235:genetics* / Q000378:metabolism*; D004268:DNA-Binding Proteins / Q000378:metabolism; D004926:Escherichia coli / Q000235:genetics / Q000378:metabolism; D029968:Escherichia coli Proteins / Q000235:genetics* / Q000378:metabolism*; D036781:Fimbriae Proteins / Q000235:genetics* / Q000378:metabolism*; D020869:Gene Expression Profiling / Q000379:methods; D008969:Molecular Sequence Data; D009698:Nucleoproteins / Q000235:genetics; D010957:Plasmids / Q000235:genetics*; D054730:Protein Interaction Domains and Motifs / Q000235:genetics
chemical_list: D001426:Bacterial Proteins; D004268:DNA-Binding Proteins; D029968:Escherichia coli Proteins; C529458:FimG protein, E coli; D009698:Nucleoproteins; D036781:Fimbriae Proteins