title: Proteomic analysis of Herbaspirillum seropedicae reveals ammonium-induced AmtB-dependent membrane sequestration of PII proteins.
abstract: This study was aimed at describing the spectrum and dynamics of proteins associated with the membrane in the nitrogen-fixing bacterium Herbaspirillum seropedicae according to the availability of fixed nitrogen. Using two-dimensional electrophoresis we identified 79 protein spots representing 45 different proteins in the membrane fraction of H. seropedicae. Quantitative analysis of gel images of membrane extracts indicated two spots with increased levels when cells were grown under nitrogen limitation in comparison with nitrogen sufficiency; these spots were identified as the GlnK protein and as a conserved noncytoplasmic protein of unknown function which was encoded in an operon together with GlnK and AmtB. Comparison of gel images of membrane extracts from cells grown under nitrogen limitation or under the same regime but collected after an ammonium shock revealed two proteins, GlnB and GlnK, with increased levels after the shock. The P(II) proteins were not present in the membrane fraction of an amtB mutant. The results reported here suggest that changes in the cellular localization of P(II) might play a role in the control of nitrogen metabolism in H. seropedicae.
authors.affiliation: Department of Biochemistry and Molecular Biology, National Institute of Science and Technology for Biological Nitrogen Fixation, Universidade Federal do Paraná, Curitiba, Brazil. huergo@ufpr.br
authors.forename: Luciano F
authors.initials: LF
authors.lastname: Huergo
authors.forename: Lilian
authors.initials: L
authors.lastname: Noindorf
authors.forename: Camila
authors.initials: C
authors.lastname: Gimenes
authors.forename: Renato S P
authors.initials: RS
authors.lastname: Lemgruber
authors.forename: Daniela F
authors.initials: DF
authors.lastname: Cordellini
authors.forename: Lucas J
authors.initials: LJ
authors.lastname: Falarz
authors.forename: Leonardo M
authors.initials: LM
authors.lastname: Cruz
authors.forename: Rose A
authors.initials: RA
authors.lastname: Monteiro
authors.forename: Fábio O
authors.initials: FO
authors.lastname: Pedrosa
authors.forename: Leda S
authors.initials: LS
authors.lastname: Chubatsu
authors.forename: Emanuel M
authors.initials: EM
authors.lastname: Souza
authors.forename: Maria B R
authors.initials: MB
authors.lastname: Steffens
mesh_terms: D001426:Bacterial Proteins / Q000032:analysis; D027682:Cation Transport Proteins / Q000032:analysis; D002462:Cell Membrane / Q000737:chemistry*; D015180:Electrophoresis, Gel, Two-Dimensional; D015964:Gene Expression Regulation, Bacterial; D015971:Gene Expression Regulation, Enzymologic; D042803:Herbaspirillum / Q000737:chemistry* / Q000502:physiology; D026901:Membrane Transport Proteins / Q000032:analysis*; D020543:Proteome / Q000032:analysis*; D000644:Quaternary Ammonium Compounds / Q000378:metabolism*; D019032:Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization
chemical_list: D001426:Bacterial Proteins; D027682:Cation Transport Proteins; D026901:Membrane Transport Proteins; D020543:Proteome; D000644:Quaternary Ammonium Compounds