title: Zinc and ATP binding of the hexameric AAA-ATPase PilF from Thermus thermophilus: role in complex stability, piliation, adhesion, twitching motility, and natural transformation.
abstract: The traffic AAA-ATPase PilF is essential for pilus biogenesis and natural transformation of Thermus thermophilus HB27. Recently, we showed that PilF forms hexameric complexes containing six zinc atoms coordinated by conserved tetracysteine motifs. Here we report that zinc binding is essential for complex stability. However, zinc binding is neither required for pilus biogenesis nor natural transformation. A number of the mutants did not exhibit any pili during growth at 64 °C but still were transformable. This leads to the conclusion that type 4 pili and the DNA translocator are distinct systems. At lower growth temperatures (55 °C) the zinc-depleted multiple cysteine mutants were hyperpiliated but defective in pilus-mediated twitching motility. This provides evidence that zinc binding is essential for the role of PilF in pilus dynamics. Moreover, we found that zinc binding is essential for complex stability but dispensable for ATPase activity. In contrast to many polymerization ATPases from mesophilic bacteria, ATP binding is not required for PilF complex formation; however, it significantly increases complex stability. These data suggest that zinc and ATP binding increase complex stability that is important for functionality of PilF under extreme environmental conditions.
authors.affiliation: Molecular Microbiology and Bioenergetics, Institute of Molecular Biosciences, Goethe University Frankfurt, 60438 Frankfurt am Main, Germany.
authors.forename: Ralf
authors.initials: R
authors.lastname: Salzer
authors.affiliation: Molecular Microbiology, Institute for Biology/Microbiology, Martin Luther University, 06120 Halle-Wittenberg, Germany.
authors.forename: Martin
authors.initials: M
authors.lastname: Herzberg
authors.affiliation: Molecular Microbiology, Institute for Biology/Microbiology, Martin Luther University, 06120 Halle-Wittenberg, Germany.
authors.forename: Dietrich H
authors.initials: DH
authors.lastname: Nies
authors.affiliation: Department of Structural Biology, Max Planck Institute of Biophysics, Frankfurt am Main, Germany, and.
authors.forename: Friederike
authors.initials: F
authors.lastname: Joos
authors.affiliation: Department of Molecular Membrane Biology, Max Planck Institute of Biophysics, 60438 Frankfurt am Main, Germany.
authors.forename: Barbara
authors.initials: B
authors.lastname: Rathmann
authors.affiliation: Department of Molecular Membrane Biology, Max Planck Institute of Biophysics, 60438 Frankfurt am Main, Germany.
authors.forename: Yvonne
authors.initials: Y
authors.lastname: Thielmann
authors.affiliation: Molecular Microbiology and Bioenergetics, Institute of Molecular Biosciences, Goethe University Frankfurt, 60438 Frankfurt am Main, Germany,. Electronic address: averhoff@bio.uni-frankfurt.de.
authors.forename: Beate
authors.initials: B
authors.lastname: Averhoff
mesh_terms: D000251:Adenosine Triphosphatases / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D000255:Adenosine Triphosphate / Q000378:metabolism*; D000266:Adenylyl Imidodiphosphate / Q000737:chemistry; D020816:Amino Acid Motifs; D019943:Amino Acid Substitution; D001422:Bacterial Adhesion; D001426:Bacterial Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D003545:Cysteine / Q000235:genetics; D004795:Enzyme Stability; D010861:Fimbriae, Bacterial / Q000201:enzymology; D011485:Protein Binding; D055503:Protein Multimerization; D016963:Thermus thermophilus / Q000201:enzymology*; D014169:Transformation, Bacterial; D015032:Zinc / Q000378:metabolism*
chemical_list: D001426:Bacterial Proteins; D000266:Adenylyl Imidodiphosphate; D000255:Adenosine Triphosphate; D000251:Adenosine Triphosphatases; D015032:Zinc; D003545:Cysteine
keywords: ATPases Associated with Diverse Cellular Activities (AAA); Cell Motility; DNA Transformation; Type IV Pili; Zinc