title: A PPM-family protein phosphatase from the thermoacidophile Thermoplasma volcanium hydrolyzes protein-bound phosphotyrosine.
abstract: The genomes of virtually all free-living archaeons encode one or more deduced protein-serine/threonine/tyrosine kinases belonging to the so-called eukaryotic protein kinase superfamily. However, the distribution of their cognate protein-serine/threonine/phosphatases displays a mosaic pattern. Thermoplasma volcanium is unique among the Archaea inasmuch as it is the sole archaeon whose complement of deduced phosphoprotein phosphatases includes a member of the PPM-family of protein-serine/threonine phosphatases--a family that originated in the Eucarya. A recombinant version of this protein, TvnPPM, exhibited protein-tyrosine phosphatase in addition to its predicted protein-serine/threonine phosphatase activity in vitro. TvnPPM is the fourth member of the PPM-family shown to exhibit such dual-specific capability, suggesting that the ancestral versions of this enzyme exhibited broad substrate specificity. Unlike most other archaeons, the genome of T. volcanium lacks open reading frames encoding stereotypical protein-tyrosine phosphatases. Hence, the dual-specificity of TvnPPM may account for its seemingly aberrant presence in an archaeon.
authors.affiliation: Department of Biochemistry, Virginia Polytechnic Institute and State University, 111C Engel Hall, Blacksburg, VA 24061, USA.
authors.forename: Hanan
authors.initials: H
authors.lastname: Dahche
authors.forename: Abdulshakur
authors.initials: A
authors.lastname: Abdullah
authors.forename: M
authors.initials: M
authors.lastname: Ben Potters
authors.forename: Peter J
authors.initials: PJ
authors.lastname: Kennelly
mesh_terms: D000595:Amino Acid Sequence; D001105:Archaea / Q000378:metabolism; D003001:Cloning, Molecular; D004926:Escherichia coli / Q000378:metabolism; D006868:Hydrolysis; D008969:Molecular Sequence Data; D016366:Open Reading Frames; D010749:Phosphoprotein Phosphatases / Q000235:genetics / Q000378:metabolism*; D019000:Phosphotyrosine / Q000737:chemistry; D010802:Phylogeny; D017386:Sequence Homology, Amino Acid; D015398:Signal Transduction; D013379:Substrate Specificity; D013822:Thermoplasma / Q000201:enzymology*; D015032:Zinc / Q000737:chemistry
chemical_list: D019000:Phosphotyrosine; D010749:Phosphoprotein Phosphatases; D015032:Zinc