title: Genome-wide analysis of substrate specificities of the Escherichia coli haloacid dehalogenase-like phosphatase family.
abstract: Haloacid dehalogenase (HAD)-like hydrolases are a vast superfamily of largely uncharacterized enzymes, with a few members shown to possess phosphatase, beta-phosphoglucomutase, phosphonatase, and dehalogenase activities. Using a representative set of 80 phosphorylated substrates, we characterized the substrate specificities of 23 soluble HADs encoded in the Escherichia coli genome. We identified small molecule phosphatase activity in 21 HADs and beta-phosphoglucomutase activity in one protein. The E. coli HAD phosphatases show high catalytic efficiency and affinity to a wide range of phosphorylated metabolites that are intermediates of various metabolic reactions. Rather than following the classical "one enzyme-one substrate" model, most of the E. coli HADs show remarkably broad and overlapping substrate spectra. At least 12 reactions catalyzed by HADs currently have no EC numbers assigned in Enzyme Nomenclature. Surprisingly, most HADs hydrolyzed small phosphodonors (acetyl phosphate, carbamoyl phosphate, and phosphoramidate), which also serve as substrates for autophosphorylation of the receiver domains of the two-component signal transduction systems. The physiological relevance of the phosphatase activity with the preferred substrate was validated in vivo for one of the HADs, YniC. Many of the secondary activities of HADs might have no immediate physiological function but could comprise a reservoir for evolution of novel phosphatases.
authors.affiliation: Banting and Best Department of Medical Research, University of Toronto, Toronto, Ontario, Canada.
authors.forename: Ekaterina
authors.initials: E
authors.lastname: Kuznetsova
authors.forename: Michael
authors.initials: M
authors.lastname: Proudfoot
authors.forename: Claudio F
authors.initials: CF
authors.lastname: Gonzalez
authors.forename: Greg
authors.initials: G
authors.lastname: Brown
authors.forename: Marina V
authors.initials: MV
authors.lastname: Omelchenko
authors.forename: Ivan
authors.initials: I
authors.lastname: Borozan
authors.forename: Liran
authors.initials: L
authors.lastname: Carmel
authors.forename: Yuri I
authors.initials: YI
authors.lastname: Wolf
authors.forename: Hirotada
authors.initials: H
authors.lastname: Mori
authors.forename: Alexei V
authors.initials: AV
authors.lastname: Savchenko
authors.forename: Cheryl H
authors.initials: CH
authors.lastname: Arrowsmith
authors.forename: Eugene V
authors.initials: EV
authors.lastname: Koonin
authors.forename: Aled M
authors.initials: AM
authors.lastname: Edwards
authors.forename: Alexander F
authors.initials: AF
authors.lastname: Yakunin
mesh_terms: D002384:Catalysis; D003001:Cloning, Molecular; D016000:Cluster Analysis; D019295:Computational Biology; D004926:Escherichia coli / Q000235:genetics*; D019143:Evolution, Molecular; D016680:Genome, Bacterial; D005947:Glucose / Q000737:chemistry; D006868:Hydrolysis; D007700:Kinetics; D005810:Multigene Family; D010744:Phosphoric Monoester Hydrolases / Q000737:chemistry / Q000235:genetics*; D010766:Phosphorylation; D015398:Signal Transduction; D013379:Substrate Specificity
chemical_list: D010744:Phosphoric Monoester Hydrolases; D005947:Glucose