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PloS One 2012The aerotolerant anaerobe Streptococcus pneumoniae is part of the normal nasopharyngeal microbiota of humans and one of the most important invasive pathogens. A genomic...
The aerotolerant anaerobe Streptococcus pneumoniae is part of the normal nasopharyngeal microbiota of humans and one of the most important invasive pathogens. A genomic survey allowed establishing the occurrence of twenty-one phosphotransferase systems, seven carbohydrate uptake ABC transporters, one sodium:solute symporter and a permease, underlining an exceptionally high capacity for uptake of carbohydrate substrates. Despite high genomic variability, combined phenotypic and genomic analysis of twenty sequenced strains did assign the substrate specificity only to two uptake systems. Systematic analysis of mutants for most carbohydrate transporters enabled us to assign a phenotype and substrate specificity to twenty-three transport systems. For five putative transporters for galactose, pentoses, ribonucleosides and sulphated glycans activity was inferred, but not experimentally confirmed and only one transport system remains with an unknown substrate and lack of any functional annotation. Using a metabolic approach, 80% of the thirty-two fermentable carbon substrates were assigned to the corresponding transporter. The complexity and robustness of sugar uptake is underlined by the finding that many transporters have multiple substrates, and many sugars are transported by more than one system. The present work permits to draw a functional map of the complete arsenal of carbohydrate utilisation proteins of pneumococci, allows re-annotation of genomic data and might serve as a reference for related species. These data provide tools for specific investigation of the roles of the different carbon substrates on pneumococcal physiology in the host during carriage and invasive infection.
Topics: ATP-Binding Cassette Transporters; Amino Acid Sequence; Carbohydrate Metabolism; Genetic Variation; Genome, Bacterial; Genomics; Microarray Analysis; Molecular Sequence Data; Phenotype; Phosphotransferases; Streptococcus pneumoniae; Substrate Specificity
PubMed: 22428019
DOI: 10.1371/journal.pone.0033320 -
Molecular Microbiology Nov 2001Mycoplasmas are unable to synthesize purine and pyrimidine bases de novo. Therefore, salvage of existing nucleosides and bases is essential for their survival. Four...
Mycoplasmas are unable to synthesize purine and pyrimidine bases de novo. Therefore, salvage of existing nucleosides and bases is essential for their survival. Four mycoplasma species were studied with regard to their ability to phosphorylate deoxynucleosides. High levels of thymidine kinase (TK), deoxycytidine kinase (dCK), deoxyguanosine kinase (dGK) and deoxyadenosine kinase (dAK) activities were detected in extracts from Mycoplasma pneumoniae, Mycoplasma mycoides subsp. mycoides SC (M. mymySC), Acholeplasma laidlawii (A. laidlawii) and Mycoplasma arginini (M. arginini). Nucleoside phosphotransferase activities were found at high levels in A. laidlawii and low levels in M. arginini. Pyrophosphate-dependent deoxynucleoside kinase activities were detected mainly in A. laidlawii and M. mymySC extracts. Two open reading frames were identified in the M. mymySC genome; one showed 25% sequence identity to human dGK and the other one had about 26% sequence identity to human TK1. The M. mymySC dGK-like enzyme was cloned, expressed in Escherichia coli and affinity-purified. This enzyme phosphorylated dAdo, dGuo and dCyd, and the highest catalytic rate was with dAdo as substrate. Therefore, we suggest that this enzyme should be named deoxyadenosine kinase. The physiological role of mycoplasma dAK and TK may be to support the unusually large dATP and dTTP pools required for replication of mycoplasma genomes.
Topics: Amino Acid Sequence; Animals; Cloning, Molecular; Deoxyadenosines; Deoxycytidine; Deoxyguanosine; Deoxyribonucleosides; Humans; Molecular Sequence Data; Mycoplasma; Phosphorylation; Phosphotransferases; Phosphotransferases (Alcohol Group Acceptor); Phylogeny; Purines; Pyrimidines; Sequence Alignment; Substrate Specificity
PubMed: 11737647
DOI: 10.1046/j.1365-2958.2001.02700.x -
Hua Xi Kou Qiang Yi Xue Za Zhi = Huaxi... Jun 2016This study aims to evaluate the effect of ptxA and ptxB genes, which are important genes in the L-ascorbate phosphotransferase system (PTS) of Streptococcus mutans (S....
OBJECTIVE
This study aims to evaluate the effect of ptxA and ptxB genes, which are important genes in the L-ascorbate phosphotransferase system (PTS) of Streptococcus mutans (S. mutans).
METHODS
The ptxA-, ptxB-, and ptxAB-double deficient mutant as well as ptxAB-complemented strain were constructed. Quantitative real-time polymerase chain reaction analysis was performed to evaluate the expression of the target genes of wild-type S. mutans when L-ascorbate was used as the sole carbohydrate source. The OD₆₀₀ values of the wild type, deficient, and complemented strains were continuously monitored, and their growth curves were constructed to compare growth capacity.
RESULTS
Polymerase chain reaction and sequencing analyses suggested that deficient and complemented strains were successfully constructed. The expression levelsof ptxA and ptxB significantly increased (P < 0.01) when L-ascorbate was used as the sole carbohydrate source. The growth capacity of the deficient mutants decreased compared with that of the wild-type strain. However, the wild-type phenotype could be restored in the complemented strain.
CONCLUSION
ptxA and ptxB genes are associated with L-ascorbate metabolism of S. mutans. The construction of deficient strains and complemented strain lay a foundation for further mechanism study on L-ascorbate metabolism in S. mutans.
Topics: Bacterial Proteins; Genes, Bacterial; Phosphotransferases; Real-Time Polymerase Chain Reaction; Streptococcus mutans; Transcription Factors
PubMed: 27526458
DOI: 10.7518/hxkq.2016.03.017 -
The Journal of Biological Chemistry May 1967
Topics: Animals; Brain; Carbon Isotopes; Chromatography, Gel; In Vitro Techniques; Mice; Phosphoric Monoester Hydrolases; Phosphotransferases; Serine; Urea
PubMed: 4290222
DOI: No ID Found -
Journal of Bacteriology Mar 2005We have cloned the gene for polyphosphate:AMP phosphotransferase (PAP), the enzyme that catalyzes phosphorylation of AMP to ADP at the expense of polyphosphate [poly(P)]...
We have cloned the gene for polyphosphate:AMP phosphotransferase (PAP), the enzyme that catalyzes phosphorylation of AMP to ADP at the expense of polyphosphate [poly(P)] in Acinetobacter johnsonii 210A. A genomic DNA library was constructed in Escherichia coli, and crude lysates of about 6,000 clones were screened for PAP activity. PAP activity was evaluated by measuring ATP produced by the coupled reactions of PAP and purified E. coli poly(P) kinases (PPKs). In this coupled reaction, PAP produces ADP from poly(P) and AMP, and the resulting ADP is converted to ATP by PPK. The isolated pap gene (1,428 bp) encodes a protein of 475 amino acids with a molecular mass of 55.8 kDa. The C-terminal region of PAP is highly homologous with PPK2 homologs isolated from Pseudomonas aeruginosa PAO1. Two putative phosphate-binding motifs (P-loops) were also identified. The purified PAP enzyme had not only strong PAP activity but also poly(P)-dependent nucleoside monophosphate kinase activity, by which it converted ribonucleoside monophosphates and deoxyribonucleoside monophosphates to ribonucleoside diphosphates and deoxyribonucleoside diphosphates, respectively. The activity for AMP was about 10 times greater than that for GMP and 770 and about 1,100 times greater than that for UMP and CMP.
Topics: Acinetobacter; Amino Acid Sequence; Molecular Sequence Data; Phosphotransferases (Phosphate Group Acceptor); Polyphosphates; Sequence Alignment; Sequence Homology, Amino Acid; Substrate Specificity
PubMed: 15716459
DOI: 10.1128/JB.187.5.1859-1865.2005 -
Proceedings of the National Academy of... Aug 2009BglG, which regulates expression of the beta-glucoside utilization (bgl) operon in Escherichia coli, represents a family of RNA-binding transcriptional antiterminators...
BglG, which regulates expression of the beta-glucoside utilization (bgl) operon in Escherichia coli, represents a family of RNA-binding transcriptional antiterminators that positively regulate transcription of sugar utilization genes in Gram-negative and Gram-positive organisms. BglG is negatively regulated by the beta-glucoside phosphotransferase, BglF, by means of phosphorylation and physical association, and it is positively regulated by the general phosphoenolpyruvate phosphotransferase system (PTS) proteins, enzyme I (EI) and HPr. We studied the positive regulation of BglG both in vitro and in vivo. Here, we show that although EI and HPr are essential for BglG activity, this mode of activation does not require phosphorylation of BglG by HPr, as opposed to the phosphorylation-mediated activation of many BglG-like antiterminators in Gram-positive organisms. The effect of EI and HPr on BglG is not mediated by BglF. Nevertheless, the release of BglG from BglF, which is stimulated by the extracellular sugar in a sugar uptake-independent manner, is a prerequisite for BglG activation. Taken together, the results indicate that activation of BglG is a 2-stage process: a sugar-stimulated release from the membrane-bound sugar sensor followed by a phosphorylation-independent stimulatory effect exerted by the general PTS proteins.
Topics: Bacterial Proteins; Escherichia coli; Escherichia coli Proteins; Models, Genetic; Monosaccharide Transport Proteins; Operon; Phosphoenolpyruvate Sugar Phosphotransferase System; Phosphorylation; Phosphotransferases; RNA-Binding Proteins; Terminator Regions, Genetic; Transcription, Genetic
PubMed: 19633194
DOI: 10.1073/pnas.0902559106 -
European Journal of Biochemistry Mar 1980An improved homogeneous preparation of adenylate kinase (ATP:AMP phosphotransferase, ATP + AMP in equilibrium 2 ADP) from baker's yeast was attained by extraction using...
An improved homogeneous preparation of adenylate kinase (ATP:AMP phosphotransferase, ATP + AMP in equilibrium 2 ADP) from baker's yeast was attained by extraction using ethyl acetate and successive column chromatography on Affi-Gel blue, Sephadex G-100, phosphocellulose and Sephacryl S-200. The overall purification is about 670-fold with a yield of 23% and final specific activity of 1900 units/mg protein. The enzyme preparation is a single band in isoelectrofocusing with a pI of 5.7. By sodium dodecyl sulfate gel electrophoresis and gel chromatography the molecular weight is 27 500. Among the nucleoside monophosphates investigated (AMP, CMP, GMP, IMP and UMP) only AMP reacts with ATP (dATP). ATP (dATP) is about one order of magnitude more active than CTP, GTP, ITP and UTP. The enzyme catalyzes only in the presence of a divalent metal cation, namely Mg2+, Ca2+, Co2+, Mn2+ and Ni2+, and the reaction rate is maximal at about 0.5 M NaCl. The binding of the substrates also takes place in the absence of metal. The dissociation constants for ATP, MgATP, CTP, GTP, UTP and AMP are 3.4, 4.2, 18.5, 17.2, 23.8 and 39.3 microM respectively. The amino acid composition of the purified enzyme is: 32 aspartic acid + asparagine, 12 threonine, 12 serine, 27 glutamic acid + glutamine, 16 proline, 21 glycine, 24 alanine, 11 valine, 9 methionine, 17 isoleucine, 25 leucine, 4 tyrosine, 7 phenylalanine, 2 half-cystine (no free sulfhydryl), 23 lysine, 6 histidine, 10 arginine and 2 tryptophan, totalling 260 residues.
Topics: Adenylate Kinase; Amino Acids; Binding Sites; Cations, Divalent; Hydrogen-Ion Concentration; Kinetics; Molecular Weight; Phosphotransferases; Saccharomyces cerevisiae; Substrate Specificity
PubMed: 6245882
DOI: 10.1111/j.1432-1033.1980.tb04477.x -
MBio Aug 2016Mycobacterium tuberculosis, the etiological agent of tuberculosis (TB), has a unique cell envelope which accounts for its unusual low permeability and contributes to...
UNLABELLED
Mycobacterium tuberculosis, the etiological agent of tuberculosis (TB), has a unique cell envelope which accounts for its unusual low permeability and contributes to resistance against common antibiotics. The main structural elements of the cell wall consist of a cross-linked network of peptidoglycan (PG) in which some of the muramic acid residues are covalently attached to a complex polysaccharide, arabinogalactan (AG), via a unique α-l-rhamnopyranose-(1→3)-α-d-GlcNAc-(1→P) linker unit. While the molecular genetics associated with PG and AG biosynthetic pathways have been largely delineated, the mechanism by which these two major pathways converge has remained elusive. In Gram-positive organisms, the LytR-CpsA-Psr (LCP) family of proteins are responsible for ligating cell wall teichoic acids to peptidoglycan, through a linker unit that bears a striking resemblance to that found in mycobacterial arabinogalactan. In this study, we have identified Rv3267 as a mycobacterial LCP homolog gene that encodes a phosphotransferase which we have named Lcp1. We demonstrate that lcp1 is an essential gene required for cell viability and show that recombinant Lcp1 is capable of ligating AG to PG in a cell-free radiolabeling assay.
IMPORTANCE
Tuberculosis is an infectious disease caused by the bacterial organism Mycobacterium tuberculosis Survival of M. tuberculosis rests critically on the integrity of its unique cell wall; therefore, a better understanding of how the genes and enzymes involved in cell wall assembly work is fundamental for us to develop new drugs to treat this disease. In this study, we have identified Lcp1 as an essential phosphotransferase that ligates together arabinogalactan and peptidoglycan, two crucial cell wall macromolecules found within the mycobacterial cell wall. The discovery of Lcp1 sheds new light on the final stages of mycobacterial cell wall assembly and represents a key biosynthetic step that could be exploited for new anti-TB drug discovery.
Topics: Galactans; Genes, Essential; Microbial Viability; Mycobacterium tuberculosis; Peptidoglycan; Phosphotransferases
PubMed: 27486192
DOI: 10.1128/mBio.00972-16 -
The Journal of Biological Chemistry Mar 1999Protozoan parasites of the genus Leishmania secrete a number of glycoproteins and mucin-like proteoglycans that appear to be important parasite virulence factors. We...
Protozoan parasites of the genus Leishmania secrete a number of glycoproteins and mucin-like proteoglycans that appear to be important parasite virulence factors. We have previously proposed that the polypeptide backbones of these molecules are extensively modified with a complex array of phosphoglycan chains that are linked to Ser/Thr-rich domains via a common Manalpha1-PO4-Ser linkage (Ilg, T., Overath, P., Ferguson, M. A. J., Rutherford, T., Campbell, D. G., and McConville, M. J. (1994) J. Biol. Chem. 269, 24073-24081). In this study, we show that Leishmania mexicana promastigotes contain a peptide-specific mannose-1-phosphotransferase (pep-MPT) activity that adds Manalpha1-P to serine residues in a range of defined peptides. The presence and location of the Manalpha1-PO4-Ser linkage in these peptides were determined by electrospray ionization mass spectrometry and chemical and enzymatic treatments. The pep-MPT activity was solubilized in non-ionic detergents, was dependent on Mn2+, utilized GDP-Man as the mannose donor, and was expressed in all developmental stages of the parasite. The pep-MPT activity was maximal against peptides containing Ser/Thr-rich domains of the endogenous acceptors and, based on competition assays with oligosaccharide acceptors, was distinct from other leishmanial MPTs involved in the initiation and elongation of lipid-linked phosphoglycan chains. In subcellular fractionation experiments, pep-MPT was resolved from the endoplasmic reticulum marker BiP, but had an overlapping distribution with the cis-Golgi marker Rab1. Although Man-PO4 residues in the mature secreted glycoproteins are extensively modified with mannose oligosaccharides and phosphoglycan chains, similar modifications were not added to peptide-linked Man-PO4 residues in the in vitro assays. Similarly, Man-PO4 residues on endogenous polypeptide acceptors were also poorly extended, although the elongating enzymes were still active, suggesting that the pep-MPT activity and elongating enzymes may be present in separate subcellular compartments.
Topics: Amino Acid Sequence; Animals; Chromatography, High Pressure Liquid; Leishmania mexicana; Mass Spectrometry; Molecular Sequence Data; Phosphotransferases (Alcohol Group Acceptor); Transferases (Other Substituted Phosphate Groups)
PubMed: 10037765
DOI: 10.1074/jbc.274.10.6678 -
Acta Crystallographica. Section F,... Feb 2008Bacterial resistance to aminoglycoside antibiotics is primarily the result of deactivation of the drugs. Three families of enzymes are responsible for this activity,...
Bacterial resistance to aminoglycoside antibiotics is primarily the result of deactivation of the drugs. Three families of enzymes are responsible for this activity, with one such family being the aminoglycoside phosphotransferases (APHs). The gene encoding one of these enzymes, aminoglycoside-2''-phosphotransferase-Ic [APH(2'')-Ic] from Enterococcus gallinarum, has been cloned and the wild-type protein (comprising 308 amino-acid residues) and three mutants that showed elevated minimum inhibitory concentrations towards gentamicin (F108L, H258L and a double mutant F108L/H258L) were expressed in Escherichia coli and subsequently purified. All APH(2'')-Ic variants were crystallized in the presence of 14-20%(w/v) PEG 4000, 0.25 M MgCl(2), 0.1 M Tris-HCl pH 8.5 and 1 mM Mg(2)GTP. The crystals belong to the monoclinic space group C2, with one molecule in the asymmetric unit. The approximate unit-cell parameters are a = 82.4, b = 54.2, c = 77.0 A, beta = 108.8 degrees. X-ray diffraction data were collected to approximately 2.15 A resolution from an F108L crystal at beamline BL9-2 at SSRL, Stanford, California, USA.
Topics: Cloning, Molecular; Crystallization; Crystallography, X-Ray; Enterococcus; Phosphotransferases (Alcohol Group Acceptor); Protein Conformation; Recombinant Proteins
PubMed: 18259066
DOI: 10.1107/S1744309108001450