title: The ATPase of the phi29 DNA packaging motor is a member of the hexameric AAA+ superfamily.
abstract: The AAA+ superfamily of proteins is a class of motor ATPases performing a wide range of functions that typically exist as hexamers. The ATPase of phi29 DNA packaging motor has long been a subject of debate in terms of stoichiometry and mechanism of action. Here, we confirmed the stoichiometry of phi29 motor ATPase to be a hexamer and provide data suggesting that the phi29 motor ATPase is a member of the classical hexameric AAA+ superfamily. Native PAGE, EMSA, capillary electrophoresis, ATP titration, and binomial distribution assay show that the ATPase is a hexamer. Mutations in the known Walker motifs of the ATPase validated our previous assumptions that the protein exists as another member of this AAA+ superfamily. Our data also supports the finding that the phi29 DNA packaging motor uses a revolution mechanism without rotation or coiling (Schwartz et al., this issue).
authors.affiliation: Nanobiotechnology Center, College of Pharmacy and Markey Cancer Center, University of Kentucky, Lexington, KY, USA.
authors.forename: Chad
authors.initials: C
authors.lastname: Schwartz
authors.forename: Gian Marco
authors.initials: GM
authors.lastname: De Donatis
authors.forename: Huaming
authors.initials: H
authors.lastname: Fang
authors.forename: Peixuan
authors.initials: P
authors.lastname: Guo
mesh_terms: D000251:Adenosine Triphosphatases / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism; D000255:Adenosine Triphosphate / Q000378:metabolism; D017103:Bacillus Phages / Q000737:chemistry / Q000201:enzymology* / Q000502:physiology; D004252:DNA Mutational Analysis; D042003:DNA Packaging; D004268:DNA-Binding Proteins / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism; D019075:Electrophoresis, Capillary; D004591:Electrophoresis, Polyacrylamide Gel; D024202:Electrophoretic Mobility Shift Assay; D018625:Microscopy, Atomic Force; D008954:Models, Biological; D008958:Models, Molecular; D050505:Mutant Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D055503:Protein Multimerization
chemical_list: D004268:DNA-Binding Proteins; D050505:Mutant Proteins; D000255:Adenosine Triphosphate; D000251:Adenosine Triphosphatases; C439525:protein p16, bacteriophage phi29