title: Dissection of the region of Pseudomonas aeruginosa ParA that is important for dimerization and interactions with its partner ParB.
abstract: Pseudomonas aeruginosa ParA belongs to a large subfamily of Walker-type ATPases acting as partitioning proteins in bacteria. ParA has the ability to both self-associate and interact with its partner ParB. Analysis of the deletion mutants defined the part of the protein involved in dimerization and interactions with ParB. Here, a set of ParA alanine substitution mutants in the region between E67 and L85 was created and analysed in vivo and in vitro. All mutants impaired in dimerization (substitutions at positions M74, H79, Y82 and L84) were also defective in interactions with ParB, suggesting that ParA-ParB interactions depend on the ability of ParA to dimerize. Mutants with alanine substitutions at positions E67, C68, L70, E72, F76, Q83 and L85 were not impaired in dimerization, but were defective in interactions with ParB. The dimerization interface partly overlapped the pseudo-hairpin, involved in interactions with ParB. ParA mutant derivatives tested in vitro showed no defects in ATPase activity. Two parA alleles (parA84, whose product can neither self-interact nor interact with ParB, and parA67, whose product is impaired in interactions with ParB, but not in dimerization) were introduced into the P. aeruginosa chromosome by homologous gene exchange. Both mutants showed defective separation of ParB foci, but to different extents. Only PAO1161 parA84 was visibly impaired in terms of chromosome segregation, growth rate and motility, similar to a parA-null mutant.
authors.affiliation: Institute of Biochemistry and Biophysics, Polish Academy of Sciences, Pawinskiego 5A, 02-106 Warsaw, Poland.
authors.forename: Aneta A
authors.initials: AA
authors.lastname: Bartosik
authors.affiliation: Institute of Biochemistry and Biophysics, Polish Academy of Sciences, Pawinskiego 5A, 02-106 Warsaw, Poland.
authors.forename: Krzysztof
authors.initials: K
authors.lastname: Glabski
authors.affiliation: Institute of Biochemistry and Biophysics, Polish Academy of Sciences, Pawinskiego 5A, 02-106 Warsaw, Poland.
authors.forename: Paulina
authors.initials: P
authors.lastname: Jecz
authors.affiliation: Institute of Biochemistry and Biophysics, Polish Academy of Sciences, Pawinskiego 5A, 02-106 Warsaw, Poland.
authors.forename: Krzysztof
authors.initials: K
authors.lastname: Lasocki
authors.affiliation: Institute of Biochemistry and Biophysics, Polish Academy of Sciences, Pawinskiego 5A, 02-106 Warsaw, Poland.
authors.forename: Malgorzata
authors.initials: M
authors.lastname: Mikosa
authors.affiliation: Institute of Biochemistry and Biophysics, Polish Academy of Sciences, Pawinskiego 5A, 02-106 Warsaw, Poland.
authors.forename: Danuta
authors.initials: D
authors.lastname: Plochocka
authors.affiliation: School of Biosciences, University of Birmingham, Edgbaston, Birmingham B15 2TT, UK.
authors.forename: Christopher M
authors.initials: CM
authors.lastname: Thomas
authors.affiliation: Institute of Biochemistry and Biophysics, Polish Academy of Sciences, Pawinskiego 5A, 02-106 Warsaw, Poland.
authors.forename: Grazyna
authors.initials: G
authors.lastname: Jagura-Burdzy
mesh_terms: D020816:Amino Acid Motifs; D000595:Amino Acid Sequence; D019943:Amino Acid Substitution; D001426:Bacterial Proteins / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism*; D019281:Dimerization; D008969:Molecular Sequence Data; D011485:Protein Binding; D011550:Pseudomonas aeruginosa / Q000737:chemistry / Q000201:enzymology* / Q000235:genetics / Q000378:metabolism; D016415:Sequence Alignment
chemical_list: D001426:Bacterial Proteins; C052883:chromosome partition proteins, bacterial