title: The Type IV Pilus Assembly ATPase PilB of Myxococcus xanthus Interacts with the Inner Membrane Platform Protein PilC and the Nucleotide-binding Protein PilM.
abstract: Type IV pili (T4P) are ubiquitous bacterial cell surface structures, involved in processes such as twitching motility, biofilm formation, bacteriophage infection, surface attachment, virulence, and natural transformation. T4P are assembled by machinery that can be divided into the outer membrane pore complex, the alignment complex that connects components in the inner and outer membrane, and the motor complex in the inner membrane and cytoplasm. Here, we characterize the inner membrane platform protein PilC, the cytosolic assembly ATPase PilB of the motor complex, and the cytosolic nucleotide-binding protein PilM of the alignment complex of the T4P machinery ofMyxococcus xanthus PilC was purified as a dimer and reconstituted into liposomes. PilB was isolated as a monomer and bound ATP in a non-cooperative manner, but PilB fused to Hcp1 ofPseudomonas aeruginosaformed a hexamer and bound ATP in a cooperative manner. Hexameric but not monomeric PilB bound to PilC reconstituted in liposomes, and this binding stimulated PilB ATPase activity. PilM could only be purified when it was stabilized by a fusion with a peptide corresponding to the first 16 amino acids of PilN, supporting an interaction between PilM and PilN(1-16). PilM-N(1-16) was isolated as a monomer that bound but did not hydrolyze ATP. PilM interacted directly with PilB, but only with PilC in the presence of PilB, suggesting an indirect interaction. We propose that PilB interacts with PilC and with PilM, thus establishing the connection between the alignment and the motor complex.
authors: From the Department of Ecophysiology, Max Planck Institute for Terrestrial Microbiology, D-35043 Marburg and the Institute of Biology II, Molecular Biology of Archaea, University of Freiburg, D-79104 Freiburg, Germany.
authors: Lisa Franziska
authors: LF
authors: Bischof
authors: From the Department of Ecophysiology, Max Planck Institute for Terrestrial Microbiology, D-35043 Marburg and.
authors: Carmen
authors: C
authors: Friedrich
authors: From the Department of Ecophysiology, Max Planck Institute for Terrestrial Microbiology, D-35043 Marburg and.
authors: Andrea
authors: A
authors: Harms
authors: From the Department of Ecophysiology, Max Planck Institute for Terrestrial Microbiology, D-35043 Marburg and.
authors: Lotte
authors: L
authors: Søgaard-Andersen
authors: From the Department of Ecophysiology, Max Planck Institute for Terrestrial Microbiology, D-35043 Marburg and the Institute of Biology II, Molecular Biology of Archaea, University of Freiburg, D-79104 Freiburg, Germany chris.van.der.does@biologie.uni-freiburg.de.
authors: Chris
authors: C
authors: van der Does
mesh_terms: D000251:Adenosine Triphosphatases / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism; D000255:Adenosine Triphosphate / Q000737:chemistry / Q000378:metabolism; D001422:Bacterial Adhesion; D003001:Cloning, Molecular; D004926:Escherichia coli / Q000235:genetics / Q000378:metabolism; D036781:Fimbriae Proteins / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism; D010861:Fimbriae, Bacterial / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism; D015870:Gene Expression; D007700:Kinetics; D008081:Liposomes / Q000737:chemistry / Q000378:metabolism; D020409:Molecular Motor Proteins / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism; D016941:Myxococcus xanthus / Q000235:genetics* / Q000378:metabolism / Q000472:pathogenicity*; D009711:Nucleotides / Q000737:chemistry / Q000378:metabolism; D011485:Protein Binding; D055503:Protein Multimerization; D011550:Pseudomonas aeruginosa / Q000235:genetics / Q000378:metabolism; D011993:Recombinant Fusion Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D014774:Virulence; D037521:Virulence Factors / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism
chemical_list: D008081:Liposomes; D020409:Molecular Motor Proteins; D009711:Nucleotides; D011993:Recombinant Fusion Proteins; D037521:Virulence Factors; D036781:Fimbriae Proteins; D000255:Adenosine Triphosphate; D000251:Adenosine Triphosphatases
keywords: ATPase; Myxococcus xanthus; cell motility; membrane reconstitution; membrane transport; secretion; type IV pili