title: A hybrid two-component system protein from Azospirillum brasilense Sp7 was involved in chemotaxis.
abstract: We here report the sequence and functional analysis of org35 of Azospirillum brasilense Sp7, which was originally identified to be able to interact with NifA in yeast-two-hybrid system. The org35 encodes a hybrid two-component system protein, including N-terminal PAS domains, a histidine kinase (HPK) domain and a response regulator (RR) domain in C-terminal. To determine the function of the Org35, a deletion-insertion mutant in PAS domain [named Sp7353] and a complemental strain Sp7353C were constructed. The mutant had reduced chemotaxis ability compared to that of wild-type, and the complemental strain was similar to the wild-type strain. These data suggested that the A. brasilense org35 played a key role in chemotaxis. Variants containing different domains of the org35 were expressed, and the functions of these domains were studied in vitro. Phosphorylation assays in vitro demonstrated that the HPK domain of Org35 possessed the autokinase activity and that the phosphorylated HPK was able to transfer phosphate groups to the RR domain. The result indicated Org35 was a phosphorylation-communicating protein.
authors.affiliation: State Key Laboratory of Agrobiotechnology and College of Biological Sciences, China Agricultural University, Beijing 100193, PR China.
authors.forename: Yanhua
authors.initials: Y
authors.lastname: Cui
authors.forename: Ran
authors.initials: R
authors.lastname: Tu
authors.forename: Lixian
authors.initials: L
authors.lastname: Wu
authors.forename: Yuanyuan
authors.initials: Y
authors.lastname: Hong
authors.forename: Sanfeng
authors.initials: S
authors.lastname: Chen
mesh_terms: D000595:Amino Acid Sequence; D015806:Azospirillum brasilense / Q000737:chemistry / Q000235:genetics / Q000502:physiology*; D001426:Bacterial Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D002633:Chemotaxis; D015964:Gene Expression Regulation, Bacterial; D008969:Molecular Sequence Data; D017434:Protein Structure, Tertiary; D016415:Sequence Alignment
chemical_list: D001426:Bacterial Proteins