Publications

• Genome-wide analysis of substrate specificities of the Escherichia coli haloacid dehalogenase-like phosphatase family.

  Kuznetsova E., Proudfoot M., Gonzalez C.F., Brown G., Omelchenko M.V., Borozan I., Carmel L., Wolf Y.I., Mori H., Savchenko A.V., Arrowsmith C.H., Koonin E.V., Edwards A.M., Yakunin A.F.

  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 ... >> More

  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. << Less

  J. Biol. Chem. 281:36149-36161(2006) [PubMed] [EuropePMC]

  This publication is cited by 7 other entries.

• Characterization of M. tuberculosis SerB2, an essential HAD-family phosphatase, reveals novel properties.

  Yadav G.P., Shree S., Maurya R., Rai N., Singh D.K., Srivastava K.K., Ramachandran R.

  M. tuberculosis harbors an essential phosphoserine phosphatase (MtSerB2, Rv3042c) that contains two small-molecule binding ACT-domains (Pfam 01842) at the N-terminus followed by the phosphoserine phosphatase (PSP) domain. We found that exogenously added MtSerB2 elicits microtubule rearrangements i ... >> More

  M. tuberculosis harbors an essential phosphoserine phosphatase (MtSerB2, Rv3042c) that contains two small-molecule binding ACT-domains (Pfam 01842) at the N-terminus followed by the phosphoserine phosphatase (PSP) domain. We found that exogenously added MtSerB2 elicits microtubule rearrangements in THP-1 cells. Mutational analysis demonstrates that phosphatase activity is co-related to the elicited rearrangements, while addition of the ACT-domains alone elicits no rearrangements. The enzyme is dimeric, exhibits divalent metal-ion dependency, and is more specific for l-phosphoserine unlike other classical PSPases. Binding of a variety of amino acids to the ACT-domains influences MtSerB2 activity by either acting as activators/inhibitors/have no effects. Additionally, reduced activity of the PSP domain can be enhanced by equimolar addition of the ACT domains. Further, we identified that G18 and G108 of the respective ACT-domains are necessary for ligand-binding and their mutations to G18A and G108A abolish the binding of ligands like l-serine. A specific transition to higher order oligomers is observed upon the addition of l-serine at ∼0.8 molar ratio as supported by Isothermal calorimetry and Size exclusion chromatography experiments. Mutational analysis shows that the transition is dependent on binding of l-serine to the ACT-domains. Furthermore, the higher-order oligomeric form of MtSerB2 is inactive, suggesting that its formation is a mechanism for feedback control of enzyme activity. Inhibition studies involving over eight inhibitors, MtSerB2, and the PSP domain respectively, suggests that targeting the ACT-domains can be an effective strategy for the development of inhibitors. << Less

  PLoS ONE 9:E115409-E115409(2014) [PubMed] [EuropePMC]

  This publication is cited by 1 other entry.

• Plastidic pathway of serine biosynthesis. Molecular cloning and expression of 3-phosphoserine phosphatase from Arabidopsis thaliana.

  Ho C.-L., Noji M., Saito K.

  In plants, Ser is biosynthesized by two different pathways: a photorespiratory pathway via Gly and a plastidic pathway via the phosphorylated metabolites from 3-phosphoglycerate. In contrast to the better characterization of the photorespiratory pathway at a molecular level, the molecular regulati ... >> More

  In plants, Ser is biosynthesized by two different pathways: a photorespiratory pathway via Gly and a plastidic pathway via the phosphorylated metabolites from 3-phosphoglycerate. In contrast to the better characterization of the photorespiratory pathway at a molecular level, the molecular regulation and significance of the plastidic pathway are not yet well understood. An Arabidopsis thaliana cDNA encoding 3-phosphoserine phosphatase, the enzyme that is responsible for the conversion of 3-phosphoserine to Ser in the final step of the plastidic pathway of Ser biosynthesis, was cloned by functional complementation of an Escherichia coli serB-mutant. The 1.1-kilobase pair full-length cDNA, encoding 295 amino acids in its open reading frame, contains a putative organelle targeting presequence. Chloroplastic targeting has been demonstrated by particle gun bombardment using an N-terminal 60-amino acid green fluorescence protein fusion protein. Southern hybridization suggested the existence of a single-copy gene that mapped to chromosome 1. 3-Phosphoserine phosphatase enzyme activity was detected in vitro in the overexpressed protein in E. coli. Northern analysis revealed preferential gene expression in leaf and root tissues of light-grown plants with an approximately 1.5-fold abundance in the root compared with the leaf tissues. This indicates the possible role of the plastidic pathway in supplying Ser to non-photosynthetic tissues, in contrast to the function of the photorespiratory pathway in photosynthetic tissues. This work completes the molecular cloning and characterization of the three genes involved in the plastidic pathway of Ser biosynthesis in higher plants. << Less

  J. Biol. Chem. 274:11007-11012(1999) [PubMed] [EuropePMC]

  This publication is cited by 1 other entry.

• Discovery and analysis of cofactor-dependent phosphoglycerate mutase homologs as novel phosphoserine phosphatases in Hydrogenobacter thermophilus.

  Chiba Y., Oshima K., Arai H., Ishii M., Igarashi Y.

  Phosphoserine phosphatase (PSP) catalyzes the dephosphorylation of phosphoserine to serine and inorganic phosphate. PSPs, which have been found in all three domains of life, belong to the haloacid dehalogenase-like hydrolase superfamily. However, certain organisms, particularly bacteria, lack a cl ... >> More

  Phosphoserine phosphatase (PSP) catalyzes the dephosphorylation of phosphoserine to serine and inorganic phosphate. PSPs, which have been found in all three domains of life, belong to the haloacid dehalogenase-like hydrolase superfamily. However, certain organisms, particularly bacteria, lack a classical PSP gene, although they appear to possess a functional phosphoserine synthetic pathway. The apparent lack of a PSP ortholog in Hydrogenobacter thermophilus, an obligately chemolithoautotrophic and thermophilic bacterium, represented a missing link in serine anabolism because our previous study suggested that serine should be synthesized from phosphoserine. Here, we detected PSP activity in cell-free extracts of H. thermophilus and purified two proteins with PSP activity. Surprisingly, these proteins belonged to the histidine phosphatase superfamily and had been annotated as cofactor-dependent phosphoglycerate mutase (dPGM). However, because they possessed neither mutase activity nor the residues important for the activity, we defined these proteins as novel-type PSPs. Considering the strict substrate specificity toward l-phosphoserine, kinetic parameters, and PSP activity levels in cell-free extracts, these proteins were strongly suggested to function as PSPs in vivo. We also detected PSP activity from "dPGM-like" proteins of Thermus thermophilus and Arabidopsis thaliana, suggesting that PSP activity catalyzed by dPGM-like proteins may be distributed among a broad range of organisms. In fact, a number of bacterial genera, including Firmicutes and Cyanobacteria, were proposed to be strong candidates for possessing this novel type of PSP. These findings will help to identify the missing link in serine anabolism. << Less

  J. Biol. Chem. 287:11934-11941(2012) [PubMed] [EuropePMC]

  This publication is cited by 1 other entry.

• Molecular basis for the local conformational rearrangement of human phosphoserine phosphatase.

  Kim H.Y., Heo Y.S., Kim J.H., Park M.H., Moon J., Kim E., Kwon D., Yoon J., Shin D., Jeong E.J., Park S.Y., Lee T.G., Jeon Y.H., Ro S., Cho J.M., Hwang K.Y.

  Human phosphoserine phosphatase (HPSP) regulates the levels of glycine and d-serine, the putative co-agonists for the glycine site of the NMDA receptor in the brain. Here, we describe the first crystal structures of the HPSP in complexes with the competitive inhibitor 2-amino-3-phosphonopropionic ... >> More

  Human phosphoserine phosphatase (HPSP) regulates the levels of glycine and d-serine, the putative co-agonists for the glycine site of the NMDA receptor in the brain. Here, we describe the first crystal structures of the HPSP in complexes with the competitive inhibitor 2-amino-3-phosphonopropionic acid (AP3) at 2.5 A, and the phosphate ion (Pi) and the product uncompetitive inhibitor l-serine (HPSP.l-Ser.Pi) at 2.8 A. The complex structures reveal that the open-closed environmental change of the active site, generated by local rearrangement of the alpha-helical bundle domain, is important to substrate recognition and hydrolysis. The maximal extent of this structural rearrangement is shown to be about 13 A at the L4 loop and about 25 degrees at the helix alpha3. Both the structural change and mutagenesis data suggest that Arg-65 and Glu-29 play an important role in the binding of the substrate. Interestingly, the AP3 binding mode turns out to be significantly different from that of the natural substrate, phospho-l-serine, and the HPSP.l-Ser.Pi structure provides a structural basis for the feedback control mechanism of serine. These analyses allow us to provide a clear model for the mechanism of HPSP and a framework for structure-based drug development. << Less

  J. Biol. Chem. 277:46651-46658(2002) [PubMed] [EuropePMC]

  This publication is cited by 1 other entry.

• Discovery and analysis of a novel type of the serine biosynthetic enzyme phosphoserine phosphatase in Thermus thermophilus.

  Chiba Y., Yoshida A., Shimamura S., Kameya M., Tomita T., Nishiyama M., Takai K.

  Studying the diversity of extant metabolisms and enzymes, especially those involved in the biosynthesis of primary metabolites including amino acids, is important to shed light on the evolution of life. Many organisms synthesize serine from phosphoserine via a reaction catalyzed by phosphoserine p ... >> More

  Studying the diversity of extant metabolisms and enzymes, especially those involved in the biosynthesis of primary metabolites including amino acids, is important to shed light on the evolution of life. Many organisms synthesize serine from phosphoserine via a reaction catalyzed by phosphoserine phosphatase (PSP). Two types of PSP, belonging to distinct protein superfamilies, have been reported. Genomic analyses have revealed that the thermophilic bacterium Thermus thermophilus lacks both homologs while still having the ability to synthesize serine. Here, we purified a protein from T. thermophilus which we biochemically identified as a PSP. A knockout mutant of the responsible gene (TT_C1695) was constructed, which showed serine auxotrophy. These results indicated the involvement of this gene in serine biosynthesis in T. thermophilus. TT_C1695 was originally annotated as a protein with unknown function belonging to the haloacid dehalogenase-like hydrolase (HAD) superfamily. The HAD superfamily, which comprises phosphatases against a variety of substrates, includes also the classical PSP as a member. However, the amino acid sequence of the TT_C1695 was more similar to phosphatases acting on non-phosphoserine substrates than classical PSP; therefore, a BLASTP search and phylogenetic analysis failed to predict TT_C1695 as a PSP. Our results strongly suggest that the T. thermophilus PSP and classical PSP evolved specificity for phosphoserine independently. ENZYMES: Phosphoserine phosphatase (PSP; EC 3.1.3.3); serine hydroxymethyltransferase (EC 2.1.2.1); 3-phosphoglycerate dehydrogenase (EC 1.1.1.95); 3-phosphoserine aminotransferase (EC 2.6.1.52). << Less

  FEBS J. 286:726-736(2019) [PubMed] [EuropePMC]

  This publication is cited by 1 other entry.

• How calcium inhibits the magnesium-dependent enzyme human phosphoserine phosphatase.

  Peeraer Y., Rabijns A., Collet J.F., Van Schaftingen E., De Ranter C.

  The structure of the Mg(2+)-dependent enzyme human phosphoserine phosphatase (HPSP) was exploited to examine the structural and functional role of the divalent cation in the active site of phosphatases. Most interesting is the biochemical observation that a Ca(2+) ion inhibits the activity of HPSP ... >> More

  The structure of the Mg(2+)-dependent enzyme human phosphoserine phosphatase (HPSP) was exploited to examine the structural and functional role of the divalent cation in the active site of phosphatases. Most interesting is the biochemical observation that a Ca(2+) ion inhibits the activity of HPSP, even in the presence of added Mg(2+). The sixfold coordinated Mg(2+) ion present in the active site of HPSP under normal physiological conditions, was replaced by a Ca(2+) ion by using a crystallization condition with high concentration of CaCl(2) (0.7 m). The resulting HPSP structure now shows a sevenfold coordinated Ca(2+) ion in the active site that might explain the inhibitory effect of Ca(2+) on the enzyme. Indeed, the Ca(2+) ion in the active site captures both side-chain oxygen atoms of the catalytic Asp20 as a ligand, while a Mg(2+) ion ligates only one oxygen atom of this Asp residue. The bidentate character of Asp20 towards Ca(2+) hampers the nucleophilic attack of one of the Asp20 side chain oxygen atoms on the phosphorus atom of the substrate phosphoserine. << Less

  Eur. J. Biochem. 271:3421-3427(2004) [PubMed] [EuropePMC]

  This publication is cited by 1 other entry.

• Chronophin, a novel HAD-type serine protein phosphatase, regulates cofilin-dependent actin dynamics.

  Gohla A., Birkenfeld J., Bokoch G.M.

  Cofilin is a key regulator of actin cytoskeletal dynamics whose activity is controlled by phosphorylation of a single serine residue. We report the biochemical isolation of chronophin (CIN), a unique cofilin-activating phosphatase of the haloacid dehalogenase (HAD) superfamily. CIN directly dephos ... >> More

  Cofilin is a key regulator of actin cytoskeletal dynamics whose activity is controlled by phosphorylation of a single serine residue. We report the biochemical isolation of chronophin (CIN), a unique cofilin-activating phosphatase of the haloacid dehalogenase (HAD) superfamily. CIN directly dephosphorylates cofilin with high specificity and colocalizes with cofilin in motile and dividing cells. Loss of CIN activity blocks phosphocycling of cofilin, stabilizes F-actin structures and causes massive cell division defects. Our findings identify a physiological phospho-serine protein substrate for a mammalian HAD-type phosphatase and demonstrate that CIN is an important novel regulator of cofilin-mediated actin reorganization. << Less

  Nat. Cell Biol. 7:21-29(2005) [PubMed] [EuropePMC]

  This publication is cited by 1 other entry.

• Structural characterization of the reaction pathway in phosphoserine phosphatase: crystallographic 'snapshots' of intermediate states.

  Wang W., Cho H.S., Kim R., Jancarik J., Yokota H., Nguyen H.H., Grigoriev I.V., Wemmer D.E., Kim S.-H.

  Phosphoserine phosphatase (PSP) is a member of a large class of enzymes that catalyze phosphoester hydrolysis using a phosphoaspartate-enzyme intermediate. PSP is a likely regulator of the steady-state d-serine level in the brain, which is a critical co-agonist of the N-methyl-d-aspartate type of ... >> More

  Phosphoserine phosphatase (PSP) is a member of a large class of enzymes that catalyze phosphoester hydrolysis using a phosphoaspartate-enzyme intermediate. PSP is a likely regulator of the steady-state d-serine level in the brain, which is a critical co-agonist of the N-methyl-d-aspartate type of glutamate receptors. Here, we present high-resolution (1.5-1.9 A) structures of PSP from Methanococcus jannaschii, which define the open state prior to substrate binding, the complex with phosphoserine substrate bound (with a D to N mutation in the active site), and the complex with AlF3, a transition-state analog for the phospho-transfer steps in the reaction. These structures, together with those described for the BeF3-complex (mimicking the phospho-enzyme) and the enzyme with phosphate product in the active site, provide a detailed structural picture of the full reaction cycle. The structure of the apo state indicates partial unfolding of the enzyme to allow substrate binding, with refolding in the presence of substrate to provide specificity. Interdomain and active-site conformational changes are identified. The structure with the transition state analog bound indicates a "tight" intermediate. A striking structure homology, with significant sequence conservation, among PSP, P-type ATPases and response regulators suggests that the knowledge of the PSP reaction mechanism from the structures determined will provide insights into the reaction mechanisms of the other enzymes in this family. << Less

  J. Mol. Biol. 319:421-431(2002) [PubMed] [EuropePMC]

  This publication is cited by 1 other entry.

• High-resolution structure of human phosphoserine phosphatase in open conformation.

  Peeraer Y., Rabijns A., Verboven C., Collet J.F., Van Schaftingen E., De Ranter C.

  The crystal structure of human phosphoserine phosphatase (HPSP) in the open conformation has been determined at a resolution of 1.53 A. The crystals are orthorhombic, belonging to space group C222(1), with unit-cell parameters a = 49.03, b = 130.25, c = 157.29 A. The asymmetric unit contains two m ... >> More

  The crystal structure of human phosphoserine phosphatase (HPSP) in the open conformation has been determined at a resolution of 1.53 A. The crystals are orthorhombic, belonging to space group C222(1), with unit-cell parameters a = 49.03, b = 130.25, c = 157.29 A. The asymmetric unit contains two molecules. Phase information was derived from a multiwavelength anomalous dispersion (MAD) experiment conducted at three wavelengths using a selenomethionine-derivative crystal of HPSP. The structure was refined using CNS to a final crystallographic R value of 21.6% (R(free) = 23.4%). HPSP is a dimeric enzyme responsible for the third and final step of the l-serine biosynthesis pathway. It catalyses the Mg2+-dependent hydrolysis of l-phosphoserine. Recently, the structure of HPSP in complex with an inhibitor bound to the active site has been reported to be the open conformation of the enzyme. Here, the structure of HPSP is reported in the absence of substrate in the active site. Evidence is presented that HPSP in an uncomplexed form is in an even more open conformation than in the inhibitor complex. In this state, the enzyme is partially unfolded to allow the substrate to enter the active site. Binding of the substrate causes HPSP to shift to the closed conformation by stabilizing the partially unfolded region. In the present structure a Ca2+ ion is bound to the active site and an explanation is given why HPSP is not active when in the active site Mg2+ is replaced by a Ca2+ ion. << Less

  Acta Crystallogr. D 59:971-977(2003) [PubMed] [EuropePMC]

  This publication is cited by 1 other entry.

• High throughput screen identifies small molecule inhibitors specific for Mycobacterium tuberculosis phosphoserine phosphatase.

  Arora G., Tiwari P., Mandal R.S., Gupta A., Sharma D., Saha S., Singh R.

  The emergence of drug-resistant strains of Mycobacterium tuberculosis makes identification and validation of newer drug targets a global priority. Phosphoserine phosphatase (PSP), a key essential metabolic enzyme involved in conversion of O-phospho-l-serine to l-serine, was characterized in this s ... >> More

  The emergence of drug-resistant strains of Mycobacterium tuberculosis makes identification and validation of newer drug targets a global priority. Phosphoserine phosphatase (PSP), a key essential metabolic enzyme involved in conversion of O-phospho-l-serine to l-serine, was characterized in this study. The M. tuberculosis genome harbors all enzymes involved in l-serine biosynthesis including two PSP homologs: Rv0505c (SerB1) and Rv3042c (SerB2). In the present study, we have biochemically characterized SerB2 enzyme and developed malachite green-based high throughput assay system to identify SerB2 inhibitors. We have identified 10 compounds that were structurally different from known PSP inhibitors, and few of these scaffolds were highly specific in their ability to inhibit SerB2 enzyme, were noncytotoxic against mammalian cell lines, and inhibited M. tuberculosis growth in vitro. Surface plasmon resonance experiments demonstrated the relative binding for these inhibitors. The two best hits identified in our screen, clorobiocin and rosaniline, were bactericidal in activity and killed intracellular bacteria in a dose-dependent manner. We have also identified amino acid residues critical for these SerB2-small molecule interactions. This is the first study where we validate that M. tuberculosis SerB2 is a druggable and suitable target to pursue for further high throughput assay system screening. << Less

  J. Biol. Chem. 289:25149-25165(2014) [PubMed] [EuropePMC]

  This publication is cited by 1 other entry.

• Panoramic view of a superfamily of phosphatases through substrate profiling.

  Huang H., Pandya C., Liu C., Al-Obaidi N.F., Wang M., Zheng L., Toews Keating S., Aono M., Love J.D., Evans B., Seidel R.D., Hillerich B.S., Garforth S.J., Almo S.C., Mariano P.S., Dunaway-Mariano D., Allen K.N., Farelli J.D.

  Large-scale activity profiling of enzyme superfamilies provides information about cellular functions as well as the intrinsic binding capabilities of conserved folds. Herein, the functional space of the ubiquitous haloalkanoate dehalogenase superfamily (HADSF) was revealed by screening a customize ... >> More

  Large-scale activity profiling of enzyme superfamilies provides information about cellular functions as well as the intrinsic binding capabilities of conserved folds. Herein, the functional space of the ubiquitous haloalkanoate dehalogenase superfamily (HADSF) was revealed by screening a customized substrate library against >200 enzymes from representative prokaryotic species, enabling inferred annotation of ∼35% of the HADSF. An extremely high level of substrate ambiguity was revealed, with the majority of HADSF enzymes using more than five substrates. Substrate profiling allowed assignment of function to previously unannotated enzymes with known structure, uncovered potential new pathways, and identified iso-functional orthologs from evolutionarily distant taxonomic groups. Intriguingly, the HADSF subfamily having the least structural elaboration of the Rossmann fold catalytic domain was the most specific, consistent with the concept that domain insertions drive the evolution of new functions and that the broad specificity observed in HADSF may be a relic of this process. << Less

  Proc. Natl. Acad. Sci. U.S.A. 112:E1974-E1983(2015) [PubMed] [EuropePMC]

  This publication is cited by 1 other entry.

• BeF(3)(-) acts as a phosphate analog in proteins phosphorylated on aspartate: structure of a BeF(3)(-) complex with phosphoserine phosphatase.

  Cho H., Wang W., Kim R., Yokota H., Damo S., Kim S.H., Wemmer D., Kustu S., Yan D.

  Protein phosphoaspartate bonds play a variety of roles. In response regulator proteins of two-component signal transduction systems, phosphorylation of an aspartate residue is coupled to a change from an inactive to an active conformation. In phosphatases and mutases of the haloacid dehalogenase ( ... >> More

  Protein phosphoaspartate bonds play a variety of roles. In response regulator proteins of two-component signal transduction systems, phosphorylation of an aspartate residue is coupled to a change from an inactive to an active conformation. In phosphatases and mutases of the haloacid dehalogenase (HAD) superfamily, phosphoaspartate serves as an intermediate in phosphotransfer reactions, and in P-type ATPases, also members of the HAD family, it serves in the conversion of chemical energy to ion gradients. In each case, lability of the phosphoaspartate linkage has hampered a detailed study of the phosphorylated form. For response regulators, this difficulty was recently overcome with a phosphate analog, BeF(3)(-), which yields persistent complexes with the active site aspartate of their receiver domains. We now extend the application of this analog to a HAD superfamily member by solving at 1.5-A resolution the x-ray crystal structure of the complex of BeF(3)(-) with phosphoserine phosphatase (PSP) from Methanococcus jannaschii. The structure is comparable to that of a phosphoenzyme intermediate: BeF(3)(-) is bound to Asp-11 with the tetrahedral geometry of a phosphoryl group, is coordinated to Mg(2+), and is bound to residues surrounding the active site that are conserved in the HAD superfamily. Comparison of the active sites of BeF(3)(-) x PSP and BeF(3)(-) x CeY, a receiver domain/response regulator, reveals striking similarities that provide insights into the function not only of PSP but also of P-type ATPases. Our results indicate that use of BeF(3)(-) for structural studies of proteins that form phosphoaspartate linkages will extend well beyond response regulators. << Less

  Proc. Natl. Acad. Sci. U.S.A. 98:8525-8530(2001) [PubMed] [EuropePMC]

  This publication is cited by 1 other entry.

• The thrH gene product of Pseudomonas aeruginosa is a dual activity enzyme with a novel phosphoserine:homoserine phosphotransferase activity.

  Singh S.K., Yang K., Karthikeyan S., Huynh T., Zhang X., Phillips M.A., Zhang H.

  The thrH gene product of Pseudomonas aeruginosa has been shown to complement both homoserine kinase (thrB gene product) and phosphoserine phosphatase (serB gene product) activities in vivo. Sequence comparison has revealed that ThrH is related to phosphoserine phosphatases (PSP, EC 3.1.3.3) and be ... >> More

  The thrH gene product of Pseudomonas aeruginosa has been shown to complement both homoserine kinase (thrB gene product) and phosphoserine phosphatase (serB gene product) activities in vivo. Sequence comparison has revealed that ThrH is related to phosphoserine phosphatases (PSP, EC 3.1.3.3) and belongs to the l-2-haloacid dehalogenase-like protein superfamily. We have solved the crystal structures of ThrH in the apoform and in complex with a bound product phosphate. The structure confirms an overall fold similar to that of PSP. Most of the catalytic residues of PSP are also conserved in ThrH, suggesting that similar catalytic mechanisms are used by both enzymes. Spectrophotometry-based in vitro assays show that ThrH is indeed a phosphoserine phosphatase with a K(m) of 0.207 mm and k(cat) of 13.4 min(-1), comparable with those of other PSPs. More interestingly, using high pressure liquid chromatography-based assays, we have demonstrated that ThrH is able to further transfer the phosphoryl group to homoserine using phosphoserine as the phosphoryl group donor, indicating that ThrH has a novel phosphoserine:homoserine phosphotransferase activity. << Less

  J. Biol. Chem. 279:13166-13173(2004) [PubMed] [EuropePMC]

  This publication is cited by 1 other entry.