title: The X protein of hepatitis B virus has a ribo/deoxy ATPase activity.
abstract: The X protein (pX) of hepatitis B virus (HBV) is a general transcription regulator and directly associated with the transcription machinery. pX cannot bind DNA directly but interacts with cellular factors that bind the regulatory elements. There is an accumulation of evidence concerning different activities exerted by pX in transfected cells; nevertheless, the function and the biochemical properties of the protein are unknown. Biochemical analysis of bacterially expressed pX revealed that the protein possesses hydrolytic activity specific for adenine nucleotides with a Km of approximately 95 microM. This ATPase (dATPase) activity is not DNA-dependent. Mutation analysis revealed that the 88-119 amino-acid region of pX is required for its maximal activity. The putative involvement of (d)ATPase activity in the mechanism of transcription stimulation exerted by pX may be proposed by a certain analogy to the activity of transcription factors which participate in the initiation complex.
authors.affiliation: Department of Molecular Genetics and Virology, Weizmann Institute of Science, Rehovot, Israel.
authors.forename: T
authors.initials: T
authors.lastname: de-Medina
authors.forename: I
authors.initials: I
authors.lastname: Haviv
authors.forename: S
authors.initials: S
authors.lastname: Noiman
authors.forename: Y
authors.initials: Y
authors.lastname: Shaul
mesh_terms: D000251:Adenosine Triphosphatases / Q000378:metabolism*; D000255:Adenosine Triphosphate / Q000378:metabolism; D003001:Cloning, Molecular; D006515:Hepatitis B virus / Q000378:metabolism*; D011994:Recombinant Proteins / Q000378:metabolism; D015534:Trans-Activators / Q000378:metabolism*; D014162:Transfection; D054334:Viral Regulatory and Accessory Proteins
chemical_list: D011994:Recombinant Proteins; D015534:Trans-Activators; D054334:Viral Regulatory and Accessory Proteins; C057628:hepatitis B virus X protein; D000255:Adenosine Triphosphate; D000251:Adenosine Triphosphatases