The Experts below are selected from a list of 69 Experts worldwide ranked by ideXlab platform
Daozhong Zhang - One of the best experts on this subject based on the ideXlab platform.
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a kas iii heterodimer in Lipstatin biosynthesis nondecarboxylatively condenses c8 and c14 fatty acyl coa substrates by a variable mechanism during the establishment of a c22 aliphatic skeleton
Journal of the American Chemical Society, 2019Co-Authors: Daozhong Zhang, Fang ZhangAbstract:β-Ketoacyl-acyl carrier protein synthase-III (KAS-III) and its homologues are thiolase-fold proteins that typically behave as homodimers functioning in diverse thioester-based reactions for C–C, C–...
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A KAS-III Heterodimer in Lipstatin Biosynthesis Nondecarboxylatively Condenses C8 and C14 Fatty Acyl-CoA Substrates by a Variable Mechanism during the Establishment of a C22 Aliphatic Skeleton
2019Co-Authors: Daozhong Zhang, Fang Zhang, Wen LiuAbstract:β-Ketoacyl-acyl carrier protein synthase-III (KAS-III) and its homologues are thiolase-fold proteins that typically behave as homodimers functioning in diverse thioester-based reactions for C–C, C–O, or C–N bond formation. Here, we report an exception observed in the biosynthesis of Lipstatin. During the establishment of the C22 aliphatic skeleton of this β-lactone lipase inhibitor, LstA and LstB, which both are KAS-III homologues but phylogenetically distinct from each other, function together by forming an unusual heterodimer to catalyze a nondecarboxylating Claisen condensation of C8 and C14 fatty acyl-CoA substrates. The resulting C22 α-alkyl β-ketoacid, which is unstable and tends to be spontaneously decarboxylated to a shunt C21 hydrocarbon product, is transformed by the stereoselective β-ketoreductase LstD into a relatively stable C22 α-alkyl β-hydroxyacid for further transformation. LstAB activity tolerates changes in the stereochemistry, saturation degree, and thioester form of both long-chain fatty acyl-CoA substrates. This flexibility, along with the characterization of catalytic residues, benefits our investigations into the individual roles of the two KAS-III homologues in the heterodimer-catalyzed reactions. The large subunit LstA contains a characteristic Cys-His-Asn triad and likely reacts with C8 acyl-CoA to form an acyl-Cys enzyme intermediate. In contrast, the small subunit LstB lacks this triad but possesses a catalytic Glu residue, which can act on the C8 acyl-Cys enzyme intermediate in a substrate-dependent manner, either as a base for Cα deprotonation or as a nucleophile for a Michael-type addition-initiated cascade reaction, to produce an enolate anion for head-to-head assembly with C14 acyl-CoA through a unidirectional nucleophilic substitution. Uncovering LstAB catalysis draws attention to thiolase-fold proteins that are noncanonical in both active form and catalytic reaction/mechanism. LstAB homologues are widespread in bacteria and remain to be functionally assigned, generating great interest in their corresponding products and associated biological functions
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operon for biosynthesis of Lipstatin the beta lactone inhibitor of human pancreatic lipase
Applied and Environmental Microbiology, 2014Co-Authors: Tingli Bai, Daozhong Zhang, Wen Liu, Shuangjun Lin, Qingshan Long, Yemin Wang, Qianjin Kang, Zixin Deng, Meifeng TaoAbstract:Lipstatin, isolated from Streptomyces toxytricini as a potent and selective inhibitor of human pancreatic lipase, is a precursor for tetrahydroLipstatin (also known as orlistat, Xenical, and Alli), the only FDA-approved antiobesity medication for long-term use. Lipstatin features a 2-hexyl-3,5-dihydroxy-7,10-hexadecadienoic-β-lactone structure with an N-formyl-l-leucine group attached as an ester to the 5-hydroxy group. It has been suggested that the α-branched 3,5-dihydroxy fatty acid β-lactone moiety of Lipstatin in S. toxytricini is derived from Claisen condensation between two fatty acid substrates, which are derived from incomplete oxidative degradation of linoleic acid based on feeding experiments. In this study, we identified a six-gene operon (lst) that was essential for the biosynthesis of Lipstatin by large-deletion, complementation, and single-gene knockout experiments. lstA, lstB, and lstC, which encode two β-ketoacyl-acyl carrier protein synthase III homologues and an acyl coenzyme A (acyl-CoA) synthetase homologue, were indicated to be responsible for the generation of the α-branched 3,5-dihydroxy fatty acid backbone. Subsequently, the nonribosomal peptide synthetase (NRPS) gene lstE and the putative formyltransferase gene lstF were involved in decoration of the α-branched 3,5-dihydroxy fatty acid chain with an N-formylated leucine residue. Finally, the 3β-hydroxysteroid dehydrogenase-homologous gene lstD might be responsible for the reduction of the β-keto group of the biosynthetic intermediate, thereby facilitating the formation of the unique β-lactone ring.
Fang Zhang - One of the best experts on this subject based on the ideXlab platform.
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a kas iii heterodimer in Lipstatin biosynthesis nondecarboxylatively condenses c8 and c14 fatty acyl coa substrates by a variable mechanism during the establishment of a c22 aliphatic skeleton
Journal of the American Chemical Society, 2019Co-Authors: Daozhong Zhang, Fang ZhangAbstract:β-Ketoacyl-acyl carrier protein synthase-III (KAS-III) and its homologues are thiolase-fold proteins that typically behave as homodimers functioning in diverse thioester-based reactions for C–C, C–...
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A KAS-III Heterodimer in Lipstatin Biosynthesis Nondecarboxylatively Condenses C8 and C14 Fatty Acyl-CoA Substrates by a Variable Mechanism during the Establishment of a C22 Aliphatic Skeleton
2019Co-Authors: Daozhong Zhang, Fang Zhang, Wen LiuAbstract:β-Ketoacyl-acyl carrier protein synthase-III (KAS-III) and its homologues are thiolase-fold proteins that typically behave as homodimers functioning in diverse thioester-based reactions for C–C, C–O, or C–N bond formation. Here, we report an exception observed in the biosynthesis of Lipstatin. During the establishment of the C22 aliphatic skeleton of this β-lactone lipase inhibitor, LstA and LstB, which both are KAS-III homologues but phylogenetically distinct from each other, function together by forming an unusual heterodimer to catalyze a nondecarboxylating Claisen condensation of C8 and C14 fatty acyl-CoA substrates. The resulting C22 α-alkyl β-ketoacid, which is unstable and tends to be spontaneously decarboxylated to a shunt C21 hydrocarbon product, is transformed by the stereoselective β-ketoreductase LstD into a relatively stable C22 α-alkyl β-hydroxyacid for further transformation. LstAB activity tolerates changes in the stereochemistry, saturation degree, and thioester form of both long-chain fatty acyl-CoA substrates. This flexibility, along with the characterization of catalytic residues, benefits our investigations into the individual roles of the two KAS-III homologues in the heterodimer-catalyzed reactions. The large subunit LstA contains a characteristic Cys-His-Asn triad and likely reacts with C8 acyl-CoA to form an acyl-Cys enzyme intermediate. In contrast, the small subunit LstB lacks this triad but possesses a catalytic Glu residue, which can act on the C8 acyl-Cys enzyme intermediate in a substrate-dependent manner, either as a base for Cα deprotonation or as a nucleophile for a Michael-type addition-initiated cascade reaction, to produce an enolate anion for head-to-head assembly with C14 acyl-CoA through a unidirectional nucleophilic substitution. Uncovering LstAB catalysis draws attention to thiolase-fold proteins that are noncanonical in both active form and catalytic reaction/mechanism. LstAB homologues are widespread in bacteria and remain to be functionally assigned, generating great interest in their corresponding products and associated biological functions
Wen Liu - One of the best experts on this subject based on the ideXlab platform.
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A KAS-III Heterodimer in Lipstatin Biosynthesis Nondecarboxylatively Condenses C8 and C14 Fatty Acyl-CoA Substrates by a Variable Mechanism during the Establishment of a C22 Aliphatic Skeleton
2019Co-Authors: Daozhong Zhang, Fang Zhang, Wen LiuAbstract:β-Ketoacyl-acyl carrier protein synthase-III (KAS-III) and its homologues are thiolase-fold proteins that typically behave as homodimers functioning in diverse thioester-based reactions for C–C, C–O, or C–N bond formation. Here, we report an exception observed in the biosynthesis of Lipstatin. During the establishment of the C22 aliphatic skeleton of this β-lactone lipase inhibitor, LstA and LstB, which both are KAS-III homologues but phylogenetically distinct from each other, function together by forming an unusual heterodimer to catalyze a nondecarboxylating Claisen condensation of C8 and C14 fatty acyl-CoA substrates. The resulting C22 α-alkyl β-ketoacid, which is unstable and tends to be spontaneously decarboxylated to a shunt C21 hydrocarbon product, is transformed by the stereoselective β-ketoreductase LstD into a relatively stable C22 α-alkyl β-hydroxyacid for further transformation. LstAB activity tolerates changes in the stereochemistry, saturation degree, and thioester form of both long-chain fatty acyl-CoA substrates. This flexibility, along with the characterization of catalytic residues, benefits our investigations into the individual roles of the two KAS-III homologues in the heterodimer-catalyzed reactions. The large subunit LstA contains a characteristic Cys-His-Asn triad and likely reacts with C8 acyl-CoA to form an acyl-Cys enzyme intermediate. In contrast, the small subunit LstB lacks this triad but possesses a catalytic Glu residue, which can act on the C8 acyl-Cys enzyme intermediate in a substrate-dependent manner, either as a base for Cα deprotonation or as a nucleophile for a Michael-type addition-initiated cascade reaction, to produce an enolate anion for head-to-head assembly with C14 acyl-CoA through a unidirectional nucleophilic substitution. Uncovering LstAB catalysis draws attention to thiolase-fold proteins that are noncanonical in both active form and catalytic reaction/mechanism. LstAB homologues are widespread in bacteria and remain to be functionally assigned, generating great interest in their corresponding products and associated biological functions
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operon for biosynthesis of Lipstatin the beta lactone inhibitor of human pancreatic lipase
Applied and Environmental Microbiology, 2014Co-Authors: Tingli Bai, Daozhong Zhang, Wen Liu, Shuangjun Lin, Qingshan Long, Yemin Wang, Qianjin Kang, Zixin Deng, Meifeng TaoAbstract:Lipstatin, isolated from Streptomyces toxytricini as a potent and selective inhibitor of human pancreatic lipase, is a precursor for tetrahydroLipstatin (also known as orlistat, Xenical, and Alli), the only FDA-approved antiobesity medication for long-term use. Lipstatin features a 2-hexyl-3,5-dihydroxy-7,10-hexadecadienoic-β-lactone structure with an N-formyl-l-leucine group attached as an ester to the 5-hydroxy group. It has been suggested that the α-branched 3,5-dihydroxy fatty acid β-lactone moiety of Lipstatin in S. toxytricini is derived from Claisen condensation between two fatty acid substrates, which are derived from incomplete oxidative degradation of linoleic acid based on feeding experiments. In this study, we identified a six-gene operon (lst) that was essential for the biosynthesis of Lipstatin by large-deletion, complementation, and single-gene knockout experiments. lstA, lstB, and lstC, which encode two β-ketoacyl-acyl carrier protein synthase III homologues and an acyl coenzyme A (acyl-CoA) synthetase homologue, were indicated to be responsible for the generation of the α-branched 3,5-dihydroxy fatty acid backbone. Subsequently, the nonribosomal peptide synthetase (NRPS) gene lstE and the putative formyltransferase gene lstF were involved in decoration of the α-branched 3,5-dihydroxy fatty acid chain with an N-formylated leucine residue. Finally, the 3β-hydroxysteroid dehydrogenase-homologous gene lstD might be responsible for the reduction of the β-keto group of the biosynthetic intermediate, thereby facilitating the formation of the unique β-lactone ring.
Umesh Luthra - One of the best experts on this subject based on the ideXlab platform.
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Research Article THE ROLE OF LINOLEIC ACID, PALMITIC ACID AND LEUCINE IN Lipstatin BIOSYNTHESIS BY STREPTOMYCES TOXYTRICINI
2014Co-Authors: Umesh Luthra, R. C. DubeyAbstract:ABSTRACT: Lipstatin, a new and very potent inhibitor of pancreatic lipase, was isolated from the Streptomyces toxytricini. Lipstatin contain a beta lactone structure that probably account for the irreversible lipase inhibition. As per the biosynthetic pathway the role of linoleic acid, palmitic acid and leucine in Lipstatin biosynthesis by Streptomyces toxytricini was studied. Different oils were analyzed to measure the concentration of the linoleic acid and palmitic acid in the medium, and then the selected oil was used as media ingredients. While leucine was used as a media ingredient as well as feeding nutrient in the production medium. The Lipstatin production depends on linoleic acid palmitic acid and leucine concentration as per biochemical pathway. But in present study it was observed that in control media the Lipstatin activity was 1.108 mg/g while when we use linoleic acid and palmitic acid as media ingredients then the activity was 0.610 mg/g. Similarly in case of leucine was used as ingredient as well as feeding solution the maximum activity was observed 0.810 mg/g at 264 h. Thus, it may conclude that their is no significant impact of linoleic acid, palmitic acid and leucine as media ingredients and as a feeding solution on Lipstatin production. Key words: Lipstatin; Streptomyces toxytricini ATCC 19813, Linoleic acid, palmitic acid and leucine
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medium optimization for the production of Lipstatin by streptomyces toxytricini using full factorial design of experiment
2013Co-Authors: Umesh Luthra, Harish Kumar, Nishtha Kulshreshtha, Archana Tripathi, Aditi Trivedi, Sneha KhadpekarAbstract:Full factorial design of experiment for medium optimization was employed for Lipstatin production by Streptomyces toxytricini in shake flask study . The full factorial DOE was very much effective in screening of nutritional parameters within the stipulated time frame in a limited number of experiments. A maximum Lipstatin production was achieved 3.290 g/l with the following optimized factors: soya flour 35g/l and soya oil 25g/l. Validation experiments were also carried out to verify the adequacy and the accuracy of the model. The results also give a scope for large scale fermentation of Lipstatin production. (Luthra, U., Kumar, H., Kulshreshtha, N., Tripathi, A., Trivedi, A., Khadpekar, S., Chaturvedi, A. and Dubey, R.C. Medium optimization for the production of Lipstatin by Streptomyces toxytricini using full factorial design of experiment . Nat Sci 2013;11(7):73-76). (ISSN: 1545-0740). http://www.sciencepub.net/nature . 12
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Medium optimization for the production of Lipstatin by Streptomyces toxytricini using full factorial design of experiment
2013Co-Authors: Umesh Luthra, Harish Kumar, Nishtha Kulshreshtha, Archana Tripathi, Aditi Trivedi, Sneha Khadpekar, R. C. Dubey, Amitabh Chaturvedi, [ Luthra, U KumarAbstract:Abstract: Full factorial design of experiment for medium optimization was employed for Lipstatin production by Streptomyces toxytricini in shake flask study. The full factorial DOE was very much effective in screening of nutritional parameters within the stipulated time frame in a limited number of experiments. A maximum Lipstatin production was achieved 3.290 g/l with the following optimized factors: soya flour 35g/l and soya oil 25g/l. Validation experiments were also carried out to verify the adequacy and the accuracy of the model. The results also give a scope for large scale fermentation of Lipstatin production. [Luthra, U., Kumar, H., Kulshreshtha, N., Tripathi, A., Trivedi, A., Khadpekar, S., Chaturvedi, A. and Dubey, R.C. Medium optimization for the production of Lipstatin by Streptomyces toxytricini using full factorial design of experiment. Nat Sci 2013;1
Meifeng Tao - One of the best experts on this subject based on the ideXlab platform.
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operon for biosynthesis of Lipstatin the beta lactone inhibitor of human pancreatic lipase
Applied and Environmental Microbiology, 2014Co-Authors: Tingli Bai, Daozhong Zhang, Wen Liu, Shuangjun Lin, Qingshan Long, Yemin Wang, Qianjin Kang, Zixin Deng, Meifeng TaoAbstract:Lipstatin, isolated from Streptomyces toxytricini as a potent and selective inhibitor of human pancreatic lipase, is a precursor for tetrahydroLipstatin (also known as orlistat, Xenical, and Alli), the only FDA-approved antiobesity medication for long-term use. Lipstatin features a 2-hexyl-3,5-dihydroxy-7,10-hexadecadienoic-β-lactone structure with an N-formyl-l-leucine group attached as an ester to the 5-hydroxy group. It has been suggested that the α-branched 3,5-dihydroxy fatty acid β-lactone moiety of Lipstatin in S. toxytricini is derived from Claisen condensation between two fatty acid substrates, which are derived from incomplete oxidative degradation of linoleic acid based on feeding experiments. In this study, we identified a six-gene operon (lst) that was essential for the biosynthesis of Lipstatin by large-deletion, complementation, and single-gene knockout experiments. lstA, lstB, and lstC, which encode two β-ketoacyl-acyl carrier protein synthase III homologues and an acyl coenzyme A (acyl-CoA) synthetase homologue, were indicated to be responsible for the generation of the α-branched 3,5-dihydroxy fatty acid backbone. Subsequently, the nonribosomal peptide synthetase (NRPS) gene lstE and the putative formyltransferase gene lstF were involved in decoration of the α-branched 3,5-dihydroxy fatty acid chain with an N-formylated leucine residue. Finally, the 3β-hydroxysteroid dehydrogenase-homologous gene lstD might be responsible for the reduction of the β-keto group of the biosynthetic intermediate, thereby facilitating the formation of the unique β-lactone ring.