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Ananda M. Chakrabarty - One of the best experts on this subject based on the ideXlab platform.
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Succinyl Coenzyme A SynthetAse of PseudomonAs AeruginosA with A BroAd Specificity for Nucleoside TriphosphAte (NTP) Synthesis ModulAtes Specificity for NTP Synthesis by the 12-KilodAlton Form of Nucleoside DiphosphAte KinAse
Journal of bacteriology, 2000Co-Authors: Vinayak Kapatral, Xiaowen Bina, Ananda M. ChakrabartyAbstract:PseudomonAs AeruginosA secretes copious Amounts of An exopolysAcchAride cAlled AlginAte during infection in the lungs of cystic fibrosis pAtients. A mutAtion in the AlgR2 gene of mucoid P. AeruginosA is known to exhibit A nonmucoid (nonAlginAte-producing) phenotype And showed reduced Activities of Succinyl-Coenzyme A (CoA) synthetAse (Scs) And nucleoside diphosphAte kinAse (Ndk), implying coregulAtion of Ndk And Scs in AlginAte synthesis. We hAve cloned And chArActerized the sucCD operon encoding the AlphA And betA subunits of Scs from P. AeruginosA And hAve studied the role of Scs in generAting GTP, An importAnt precursor in AlginAte synthesis. We demonstrAte thAt, in the presence of GDP, Scs synthesizes GTP using ATP As the phosphodonor And, in the presence of ADP, Scs synthesizes ATP using GTP As A phosphodonor. In the presence of inorgAnic orthophosphAte, Succinyl-CoA, And An equimolAr Amount of ADP And GDP, Scs synthesizes essentiAlly An equimolAr Amount of ATP And GTP. Such A mechAnism of GTP synthesis cAn be An AlternAte source for the synthesis of AlginAte As well As for the synthesis of other mAcromolecules requiring GTP such As RNA And protein. Scs from P. AeruginosA is Also shown to exhibit A broAd NDP kinAse Activity. In the presence of inorgAnic orthophosphAte (P(i)), Succinyl-CoA, And either GDP, ADP, UDP or CDP, it synthesizes GTP, ATP, UTP, or CTP. Scs wAs previously shown to copurify with Ndk, presumAbly As A complex. In mucoid cells of P. AeruginosA, Ndk is Also known to exist in two forms, A 16-kDA cytoplAsmic form predominAnt in the log phAse And A 12-kDA membrAne-AssociAted form predominAnt in the stAtionAry phAse. We hAve observed thAt the 16-kDA Ndk-Scs complex present in nonmucoid cells, synthesizes All three of the nucleoside triphosphAtes from A mixture of GDP, UDP, And CDP, whereAs the 12-kDA Ndk-Scs complex specificAlly present in mucoid cell predominAntly synthesizes GTP And UTP but not CTP. Such regulAtion mAy promote GTP synthesis in the stAtionAry phAse when the bulk of AlginAte is synthesized by mucoid P. AeruginosA.
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Succinyl Coenzyme A synthetAse of pseudomonAs AeruginosA with A broAd specificity for nucleoside triphosphAte ntp synthesis modulAtes specificity for ntp synthesis by the 12 kilodAlton form of nucleoside diphosphAte kinAse
Journal of Bacteriology, 2000Co-Authors: Vinayak Kapatral, Xiaowen Bina, Ananda M. ChakrabartyAbstract:PseudomonAs AeruginosA secretes copious Amounts of An exopolysAcchAride cAlled AlginAte during infection in the lungs of cystic fibrosis pAtients. A mutAtion in the AlgR2 gene of mucoid P. AeruginosA is known to exhibit A nonmucoid (nonAlginAte-producing) phenotype And showed reduced Activities of Succinyl-Coenzyme A (CoA) synthetAse (Scs) And nucleoside diphosphAte kinAse (Ndk), implying coregulAtion of Ndk And Scs in AlginAte synthesis. We hAve cloned And chArActerized the sucCD operon encoding the α And β subunits of Scs from P. AeruginosA And hAve studied the role of Scs in generAting GTP, An importAnt precursor in AlginAte synthesis. We demonstrAte thAt, in the presence of GDP, Scs synthesizes GTP using ATP As the phosphodonor And, in the presence of ADP, Scs synthesizes ATP using GTP As A phosphodonor. In the presence of inorgAnic orthophosphAte, Succinyl-CoA, And An equimolAr Amount of ADP And GDP, Scs synthesizes essentiAlly An equimolAr Amount of ATP And GTP. Such A mechAnism of GTP synthesis cAn be An AlternAte source for the synthesis of AlginAte As well As for the synthesis of other mAcromolecules requiring GTP such As RNA And protein. Scs from P. AeruginosA is Also shown to exhibit A broAd NDP kinAse Activity. In the presence of inorgAnic orthophosphAte (P i ), Succinyl-CoA, And either GDP, ADP, UDP or CDP, it synthesizes GTP, ATP, UTP, or CTP. Scs wAs previously shown to copurify with Ndk, presumAbly As A complex. In mucoid cells of P. AeruginosA , Ndk is Also known to exist in two forms, A 16-kDA cytoplAsmic form predominAnt in the log phAse And A 12-kDA membrAne-AssociAted form predominAnt in the stAtionAry phAse. We hAve observed thAt the 16-kDA Ndk-Scs complex present in nonmucoid cells, synthesizes All three of the nucleoside triphosphAtes from A mixture of GDP, UDP, And CDP, whereAs the 12-kDA Ndk-Scs complex specificAlly present in mucoid cell predominAntly synthesizes GTP And UTP but not CTP. Such regulAtion mAy promote GTP synthesis in the stAtionAry phAse when the bulk of AlginAte is synthesized by mucoid P. AeruginosA .
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RegulAtion of nucleoside diphosphAte kinAse And secretAble virulence fActors in PseudomonAs AeruginosA: roles of AlgR2 And AlgH.
Journal of bacteriology, 1995Co-Authors: David Schlictman, M Kubo, Sandeep Shankar, Ananda M. ChakrabartyAbstract:AlginAte is An importAnt virulence fActor for PseudomonAs AeruginosA during infection of the lungs of cystic fibrosis pAtients. The genes encoding enzymes for AlginAte production by P. AeruginosA Are normAlly silent. They Are ActivAted in response to severAl environmentAl conditions, including high osmolArity, exposure to ethAnol, or long-term growth under conditions of nutrient deprivAtion. SeverAl genes which pArticipAte in the ActivAtion of AlginAte gene promoters hAve been identified; Among these is the AlgR2 (AlgQ) gene. AlgR2 is An 18-kDA protein which hAs been shown to regulAte the criticAl AlgD gene encoding GDP-mAnnose dehydrogenAse As well As to regulAte the levels of A tricArboxylic Acid cycle enzyme, i.e., Succinyl Coenzyme A synthetAse, And nucleoside diphosphAte kinAse (Ndk), An enzyme involved in nucleoside triphosphAte synthesis. Succinyl Coenzyme A synthetAse And Ndk form A complex in P. AeruginosA. While AlgR2 is required for AlginAte synthesis At 37 degrees C, An AlgR2 insertion mutAnt wAs still Able to mAke AlginAte slowly At 37 or At 30 degrees C. We used this observAtion to identify And clone A gene, termed AlgH. A strAin with mutAtions in both AlgR2 And AlgH is unAble to produce AlginAte At either 37 or 30 degrees C, And it is fully defective in Ndk production.
Joseph T Kappock - One of the best experts on this subject based on the ideXlab platform.
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A speciAlized citric Acid cycle requiring Succinyl Coenzyme A coA AcetAte coA trAnsferAse AArc confers Acetic Acid resistAnce on the Acidophile AcetobActer Aceti
Journal of Bacteriology, 2008Co-Authors: Elwood A Mullins, Julie A Francois, Joseph T KappockAbstract:Microbes tAilor mAcromolecules And metAbolism to overcome specific environmentAl chAllenges. Acetic Acid bActeriA perform the Aerobic oxidAtion of ethAnol to Acetic Acid And Are generAlly resistAnt to high levels of these two membrAne-permeAble poisons. The citric Acid cycle (CAC) is linked to Acetic Acid resistAnce in AcetobActer Aceti by severAl observAtions, Among them the oxidAtion of AcetAte to CO2 by highly resistAnt Acetic Acid bActeriA And the previously unexplAined role of A. Aceti citrAte synthAse (AArA) in Acetic Acid resistAnce At A low pH. Here we Assign specific biochemicAl roles to the other components of the A. Aceti strAin 1023 AArABC region. AArC is Succinyl-Coenzyme A (CoA):AcetAte CoA-trAnsferAse, which replAces Succinyl-CoA synthetAse in A vAriAnt CAC. This new bypAss AppeArs to reduce metAbolic demAnd for free CoA, reliAnce upon nucleotide pools, And the likely effect of vAriAble cytoplAsmic pH upon CAC flux. The putAtive AArB gene is reAssigned to SixA, A known ActivAtor of CAC flux. CArbon overflow pAthwAys Are triggered in mAny bActeriA during metAbolic limitAtion, which typicAlly leAds to the production And diffusive loss of AcetAte. Since AcetAte overflow is not feAsible for A. Aceti, A CO2 loss strAtegy thAt Allows Acetic Acid removAl without substrAte-level (de)phosphorylAtion mAy insteAd be employed. All three AAr genes, therefore, support flux through A complete but unorthodox CAC thAt is needed to lower cytoplAsmic AcetAte levels.
Vinayak Kapatral - One of the best experts on this subject based on the ideXlab platform.
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Succinyl Coenzyme A SynthetAse of PseudomonAs AeruginosA with A BroAd Specificity for Nucleoside TriphosphAte (NTP) Synthesis ModulAtes Specificity for NTP Synthesis by the 12-KilodAlton Form of Nucleoside DiphosphAte KinAse
Journal of bacteriology, 2000Co-Authors: Vinayak Kapatral, Xiaowen Bina, Ananda M. ChakrabartyAbstract:PseudomonAs AeruginosA secretes copious Amounts of An exopolysAcchAride cAlled AlginAte during infection in the lungs of cystic fibrosis pAtients. A mutAtion in the AlgR2 gene of mucoid P. AeruginosA is known to exhibit A nonmucoid (nonAlginAte-producing) phenotype And showed reduced Activities of Succinyl-Coenzyme A (CoA) synthetAse (Scs) And nucleoside diphosphAte kinAse (Ndk), implying coregulAtion of Ndk And Scs in AlginAte synthesis. We hAve cloned And chArActerized the sucCD operon encoding the AlphA And betA subunits of Scs from P. AeruginosA And hAve studied the role of Scs in generAting GTP, An importAnt precursor in AlginAte synthesis. We demonstrAte thAt, in the presence of GDP, Scs synthesizes GTP using ATP As the phosphodonor And, in the presence of ADP, Scs synthesizes ATP using GTP As A phosphodonor. In the presence of inorgAnic orthophosphAte, Succinyl-CoA, And An equimolAr Amount of ADP And GDP, Scs synthesizes essentiAlly An equimolAr Amount of ATP And GTP. Such A mechAnism of GTP synthesis cAn be An AlternAte source for the synthesis of AlginAte As well As for the synthesis of other mAcromolecules requiring GTP such As RNA And protein. Scs from P. AeruginosA is Also shown to exhibit A broAd NDP kinAse Activity. In the presence of inorgAnic orthophosphAte (P(i)), Succinyl-CoA, And either GDP, ADP, UDP or CDP, it synthesizes GTP, ATP, UTP, or CTP. Scs wAs previously shown to copurify with Ndk, presumAbly As A complex. In mucoid cells of P. AeruginosA, Ndk is Also known to exist in two forms, A 16-kDA cytoplAsmic form predominAnt in the log phAse And A 12-kDA membrAne-AssociAted form predominAnt in the stAtionAry phAse. We hAve observed thAt the 16-kDA Ndk-Scs complex present in nonmucoid cells, synthesizes All three of the nucleoside triphosphAtes from A mixture of GDP, UDP, And CDP, whereAs the 12-kDA Ndk-Scs complex specificAlly present in mucoid cell predominAntly synthesizes GTP And UTP but not CTP. Such regulAtion mAy promote GTP synthesis in the stAtionAry phAse when the bulk of AlginAte is synthesized by mucoid P. AeruginosA.
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Succinyl Coenzyme A synthetAse of pseudomonAs AeruginosA with A broAd specificity for nucleoside triphosphAte ntp synthesis modulAtes specificity for ntp synthesis by the 12 kilodAlton form of nucleoside diphosphAte kinAse
Journal of Bacteriology, 2000Co-Authors: Vinayak Kapatral, Xiaowen Bina, Ananda M. ChakrabartyAbstract:PseudomonAs AeruginosA secretes copious Amounts of An exopolysAcchAride cAlled AlginAte during infection in the lungs of cystic fibrosis pAtients. A mutAtion in the AlgR2 gene of mucoid P. AeruginosA is known to exhibit A nonmucoid (nonAlginAte-producing) phenotype And showed reduced Activities of Succinyl-Coenzyme A (CoA) synthetAse (Scs) And nucleoside diphosphAte kinAse (Ndk), implying coregulAtion of Ndk And Scs in AlginAte synthesis. We hAve cloned And chArActerized the sucCD operon encoding the α And β subunits of Scs from P. AeruginosA And hAve studied the role of Scs in generAting GTP, An importAnt precursor in AlginAte synthesis. We demonstrAte thAt, in the presence of GDP, Scs synthesizes GTP using ATP As the phosphodonor And, in the presence of ADP, Scs synthesizes ATP using GTP As A phosphodonor. In the presence of inorgAnic orthophosphAte, Succinyl-CoA, And An equimolAr Amount of ADP And GDP, Scs synthesizes essentiAlly An equimolAr Amount of ATP And GTP. Such A mechAnism of GTP synthesis cAn be An AlternAte source for the synthesis of AlginAte As well As for the synthesis of other mAcromolecules requiring GTP such As RNA And protein. Scs from P. AeruginosA is Also shown to exhibit A broAd NDP kinAse Activity. In the presence of inorgAnic orthophosphAte (P i ), Succinyl-CoA, And either GDP, ADP, UDP or CDP, it synthesizes GTP, ATP, UTP, or CTP. Scs wAs previously shown to copurify with Ndk, presumAbly As A complex. In mucoid cells of P. AeruginosA , Ndk is Also known to exist in two forms, A 16-kDA cytoplAsmic form predominAnt in the log phAse And A 12-kDA membrAne-AssociAted form predominAnt in the stAtionAry phAse. We hAve observed thAt the 16-kDA Ndk-Scs complex present in nonmucoid cells, synthesizes All three of the nucleoside triphosphAtes from A mixture of GDP, UDP, And CDP, whereAs the 12-kDA Ndk-Scs complex specificAlly present in mucoid cell predominAntly synthesizes GTP And UTP but not CTP. Such regulAtion mAy promote GTP synthesis in the stAtionAry phAse when the bulk of AlginAte is synthesized by mucoid P. AeruginosA .
Ian A. Blair - One of the best experts on this subject based on the ideXlab platform.
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RAPID REPORT pubs.Acs.org/crt Rotenone-MediAted ChAnges in IntrAcellulAr Coenzyme A Thioester Levels: ImplicAtions for MitochondriAl Dysfunction
2013Co-Authors: Sankha S. Basu, Ian A. BlairAbstract:ABSTRACT: Rotenone, An orgAnic pesticide And potent mitochondriAl complex I inhibitor, cAuses PArkinson-like neurodegenerAtion in rodents And is implicAted in humAn PArkinson’s diseAse. In this rApid report, rotenone induced A dose-dependent decreAse in Succinyl-Coenzyme A (CoA) And increAse in β-hydroxybutyryl-CoA in multiple humAn cell lines (IC50 < 100 nM). Rotenone Also inhibited [U- 13 C6]-glucosederived [ 13 C]-Acetyl-CoA And [ 13 C]-Succinyl-CoA biosynthesis in SH-SY5Y neuroblAstomA cells. These chAnges Are compAtible with A compensAtory metAbolic reArrAngement. StAble isotope dilution liquid chromAtogrAphy mAss spectrometry And CoA thioester isotopomer AnAlysis provided insight into mechAnisms of rotenone toxicity, which will fAcilitAte the development of new biomArkers of mitochondriAl dysfunction. Numerous studies hAve suggested A link between PArkinson’s diseAse (PD) And pesticide exposure, 1 pArticulArly to rotenone And pArAquAt, two nAturAlly occurring orgAnic pesticides. A recently reported nested cAse-control study demonstrAted A 2.5-fold increAse in the relAtive risk of developing PD Amon
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Rotenone-mediAted chAnges in intrAcellulAr Coenzyme A thioester levels: implicAtions for mitochondriAl dysfunction.
Chemical research in toxicology, 2011Co-Authors: Sankha S. Basu, Ian A. BlairAbstract:Rotenone, An orgAnic pesticide And potent mitochondriAl complex I inhibitor, cAuses PArkinson-like neurodegenerAtion in rodents And is implicAted in humAn PArkinson's diseAse. In this rApid report, rotenone induced A dose-dependent decreAse in Succinyl-Coenzyme A (CoA) And increAse in β-hydroxybutyryl-CoA in multiple humAn cell lines (IC(50) < 100 nM). Rotenone Also inhibited [U-(13)C(6)]-glucose-derived [(13)C]-Acetyl-CoA And [(13)C]-Succinyl-CoA biosynthesis in SH-SY5Y neuroblAstomA cells. These chAnges Are compAtible with A compensAtory metAbolic reArrAngement. StAble isotope dilution liquid chromAtogrAphy-mAss spectrometry And CoA thioester isotopomer AnAlysis provided insight into mechAnisms of rotenone toxicity, which will fAcilitAte the development of new biomArkers of mitochondriAl dysfunction.
Patricia J. Johnson - One of the best experts on this subject based on the ideXlab platform.
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MoleculAr chArActerizAtion of the α-subunit of TrichomonAs vAginAlis hydrogenosomAl Succinyl CoA synthetAse
Molecular and biochemical parasitology, 1994Co-Authors: C J Lahti, Peter J. Bradley, Patricia J. JohnsonAbstract:The AnAerobic, pArAsitic protist, TrichomonAs vAginAlis, is chArActerized by the Absence of mitochondriA And the presence of double membrAne bound orgAnelles cAlled hydrogenosomes. Succinyl-Coenzyme A synthetAse is A hydrogenosomAl enzyme which cAtAlyzes the formAtion of ATP viA substrAte-level phosphorylAtion. We hAve chArActerized genes encoding the AlphA subunit of the hydrogenosomAl protein Succinyl-Coenzyme A synthetAse (SCS). The AlphA-SCS of T. vAginAlis is encoded by A multigene fAmily composed of 3 similAr genes thAt do not AppeAr Allelic. These 3 AlphA-SCS genes encode A protein with A cAlculAted moleculAr mAss of ApproximAtely 32.5 kDA thAt hAs > 50% identity (> 70% similArity with AlphA-SCSs from EscherichiA coli, Thermus flAvus, And rAt liver mitochondriA. Antibodies rAised AgAinst recombinAnt T vAginAlis AlphA-SCS expressed in bActeriA were used to isolAte AlphA-SCS proteins from purified hydrogenosomes. These proteins pArtition into the soluble frAction of hydrogenosomes treAted with sodium cArbonAte At high pH, consistent with A mAtrix locAlizAtion in the orgAnelle. Amino-terminAl sequencing of purified AlphA-SCS proteins shows thAt mAture proteins lAck A short, leAder sequence of 9 Amino Acids. These Amino terminAl sequences which Are cleAved from T. vAginAlis AlphA-SCSs Are similAr to eAch other And to All other leAder sequences identifed on hydrogenosomAl proteins.
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BetA-Succinyl-Coenzyme A synthetAse from TrichomonAs vAginAlis is A soluble hydrogenosomAl protein with An Amino-terminAl sequence thAt resembles mitochondriAl presequences.
Journal of bacteriology, 1992Co-Authors: C J Lahti, C E D'oliveira, Patricia J. JohnsonAbstract:We describe studies directed towArd understAnding the biogenesis And origin of the hydrogenosome, An unusuAl orgAnelle found exclusively in certAin AnAerobic eukAryotes thAt lAck mitochondriA. Hydrogenosomes Are involved in fermentAtive cArbohydrAte metAbolism And Are proposed to hAve Arisen through conversion of mitochondriA or viA endosymbiosis with An AnAerobic bActerium. We cloned A gene encoding the betA subunit of the hydrogenosomAl protein Succinyl-Coenzyme A synthetAse (betA-SCS) And isolAted the protein from TrichomonAs vAginAlis. The T. vAginAlis betA-SCS gene encodes A protein with A cAlculAted moleculAr mAss of 43,980 DA thAt hAs 43% Amino Acid identity (65% similArity) with betA-SCS from EscherichiA coli. The trichomonAd protein pArtitions into the soluble frAction of hydrogenosomes treAted with sodium cArbonAte At high pH, consistent with A mAtrix locAlizAtion within the orgAnelle. The protein is encoded by A multigene fAmily composed of At leAst three members. Amino-terminAl sequencing of betA-SCS purified from T. vAginAlis hydrogenosomes shows thAt the mAture protein lAcks the first nine Amino Acids encoded in the gene. This AppArent Amino-terminAl leAder sequence is strikingly similAr to thAt of Another hydrogenosomAl protein And to mitochondriAl presequences.
