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Jan Jirschitzka - One of the best experts on this subject based on the ideXlab platform.
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Increasing the pace of new discoveries in Tropane alkaloid biosynthesis
2013Co-Authors: Jan Jirschitzka, Franziska Dolke, John C. D’auriaAbstract:Abstract Tropane alkaloids (TAs) are plant-derived natural products that have been exploited throughout history for their pharmaceutical properties. TAs are characterised by the presence of a tropane ring and are present in a variety of plant families including the Solanaceae, Convolvulaceae, Proteaceae, Rhizophoraceae, Brassicaceae and Erythroxylaceae. The structural genes and enzymes involved in TA biosynthesis have been characterised primarily in the Solanaceae, but several key steps remain unresolved. The scattered distribution of TAs in different angiosperm families suggests that there may be several alternative pathways for TA biosynthesis, and TA biosynthesis appears to have a polyphyletic origin. Molecular techniques are providing an ever-increasing amount of information on the nature and evolution of TA biosynthesis pathways and are aiding the development of techniques for increasing the production of useful tropanes through metabolic engineering.
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plant tropane alkaloid biosynthesis evolved independently in the solanaceae and Erythroxylaceae
2012Co-Authors: Jan Jirschitzka, Gregor W Schmidt, Michael Reichelt, Bernd Schneider, Jonathan Gershenzon, John C DauriaAbstract:The pharmacologically important tropane alkaloids have a scattered distribution among angiosperm families, like many other groups of secondary metabolites. To determine whether tropane alkaloids have evolved repeatedly in different lineages or arise from an ancestral pathway that has been lost in most lines, we investigated the tropinone-reduction step of their biosynthesis. In species of the Solanaceae, which produce compounds such as atropine and scopolamine, this reaction is known to be catalyzed by enzymes of the short-chain dehydrogenase/reductase family. However, in Erythroxylum coca (Erythroxylaceae), which accumulates cocaine and other tropane alkaloids, no proteins of the short-chain dehydrogenase/reductase family were found that could catalyze this reaction. Instead, purification of E. coca tropinone-reduction activity and cloning of the corresponding gene revealed that a protein of the aldo-keto reductase family carries out this reaction in E. coca. This protein, designated methylecgonone reductase, converts methylecgonone to methylecgonine, the penultimate step in cocaine biosynthesis. The protein has highest sequence similarity to other aldo-keto reductases, such as chalcone reductase, an enzyme of flavonoid biosynthesis, and codeinone reductase, an enzyme of morphine alkaloid biosynthesis. Methylecgonone reductase reduces methylecgonone (2-carbomethoxy-3-tropinone) stereospecifically to 2-carbomethoxy-3β-tropine (methylecgonine), and has its highest activity, protein level, and gene transcript level in young, expanding leaves of E. coca. This enzyme is not found at all in root tissues, which are the site of tropane alkaloid biosynthesis in the Solanaceae. This evidence supports the theory that the ability to produce tropane alkaloids has arisen more than once during the evolution of the angiosperms.
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Plant tropane alkaloid biosynthesis evolved independently in the Solanaceae and Erythroxylaceae
2012Co-Authors: Jan Jirschitzka, Gregor W Schmidt, Michael Reichelt, Bernd Schneider, Jonathan Gershenzon, John C. D’auriaAbstract:The pharmacologically important tropane alkaloids have a scattered distribution among angiosperm families, like many other groups of secondary metabolites. To determine whether tropane alkaloids have evolved repeatedly in different lineages or arise from an ancestral pathway that has been lost in most lines, we investigated the tropinone-reduction step of their biosynthesis. In species of the Solanaceae, which produce compounds such as atropine and scopolamine, this reaction is known to be catalyzed by enzymes of the short-chain dehydrogenase/reductase family. However, in Erythroxylum coca (Erythroxylaceae), which accumulates cocaine and other tropane alkaloids, no proteins of the short-chain dehydrogenase/reductase family were found that could catalyze this reaction. Instead, purification of E. coca tropinone-reduction activity and cloning of the corresponding gene revealed that a protein of the aldo-keto reductase family carries out this reaction in E. coca. This protein, designated methylecgonone reductase, converts methylecgonone to methylecgonine, the penultimate step in cocaine biosynthesis. The protein has highest sequence similarity to other aldo-keto reductases, such as chalcone reductase, an enzyme of flavonoid biosynthesis, and codeinone reductase, an enzyme of morphine alkaloid biosynthesis. Methylecgonone reductase reduces methylecgonone (2-carbomethoxy-3-tropinone) stereospecifically to 2-carbomethoxy-3β-tropine (methylecgonine), and has its highest activity, protein level, and gene transcript level in young, expanding leaves of E. coca. This enzyme is not found at all in root tissues, which are the site of tropane alkaloid biosynthesis in the Solanaceae. This evidence supports the theory that the ability to produce tropane alkaloids has arisen more than once during the evolution of the angiosperms.
John C. D’auria - One of the best experts on this subject based on the ideXlab platform.
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Increasing the pace of new discoveries in Tropane alkaloid biosynthesis
2013Co-Authors: Jan Jirschitzka, Franziska Dolke, John C. D’auriaAbstract:Abstract Tropane alkaloids (TAs) are plant-derived natural products that have been exploited throughout history for their pharmaceutical properties. TAs are characterised by the presence of a tropane ring and are present in a variety of plant families including the Solanaceae, Convolvulaceae, Proteaceae, Rhizophoraceae, Brassicaceae and Erythroxylaceae. The structural genes and enzymes involved in TA biosynthesis have been characterised primarily in the Solanaceae, but several key steps remain unresolved. The scattered distribution of TAs in different angiosperm families suggests that there may be several alternative pathways for TA biosynthesis, and TA biosynthesis appears to have a polyphyletic origin. Molecular techniques are providing an ever-increasing amount of information on the nature and evolution of TA biosynthesis pathways and are aiding the development of techniques for increasing the production of useful tropanes through metabolic engineering.
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Plant tropane alkaloid biosynthesis evolved independently in the Solanaceae and Erythroxylaceae
2012Co-Authors: Jan Jirschitzka, Gregor W Schmidt, Michael Reichelt, Bernd Schneider, Jonathan Gershenzon, John C. D’auriaAbstract:The pharmacologically important tropane alkaloids have a scattered distribution among angiosperm families, like many other groups of secondary metabolites. To determine whether tropane alkaloids have evolved repeatedly in different lineages or arise from an ancestral pathway that has been lost in most lines, we investigated the tropinone-reduction step of their biosynthesis. In species of the Solanaceae, which produce compounds such as atropine and scopolamine, this reaction is known to be catalyzed by enzymes of the short-chain dehydrogenase/reductase family. However, in Erythroxylum coca (Erythroxylaceae), which accumulates cocaine and other tropane alkaloids, no proteins of the short-chain dehydrogenase/reductase family were found that could catalyze this reaction. Instead, purification of E. coca tropinone-reduction activity and cloning of the corresponding gene revealed that a protein of the aldo-keto reductase family carries out this reaction in E. coca. This protein, designated methylecgonone reductase, converts methylecgonone to methylecgonine, the penultimate step in cocaine biosynthesis. The protein has highest sequence similarity to other aldo-keto reductases, such as chalcone reductase, an enzyme of flavonoid biosynthesis, and codeinone reductase, an enzyme of morphine alkaloid biosynthesis. Methylecgonone reductase reduces methylecgonone (2-carbomethoxy-3-tropinone) stereospecifically to 2-carbomethoxy-3β-tropine (methylecgonine), and has its highest activity, protein level, and gene transcript level in young, expanding leaves of E. coca. This enzyme is not found at all in root tissues, which are the site of tropane alkaloid biosynthesis in the Solanaceae. This evidence supports the theory that the ability to produce tropane alkaloids has arisen more than once during the evolution of the angiosperms.
Camila Holanda De ,albuquerque - One of the best experts on this subject based on the ideXlab platform.
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flavonoides glicosilados de erythroxylum pulchrum a st hil Erythroxylaceae
2014Co-Authors: Camila Holanda De ,albuquerque, Steno L Oliveira, Josean Fechine Tavares, Maria De Fatima Agra, Taina Souza Silva, Gregorio Fernandes Goncalves, Vicente Carlos De Oliveira Costa, Hilzeth De Luna Freire Pessoa, Marcelo Sobral Da SilvaAbstract:The phytochemical investigation of Erythroxylum pulchrum St. Hil. (Erythroxylaceae) led to the isolation of three known flavonoid glycosides quercetin-3-O-α-L-rhaminoside, ombuin-3-ruthinoside and ombuin-3-ruthinoside-5-glucoside. These flavonoids are being described for the first time in this E. pulchrum. The structures of the compounds were determined by analysis of IR, MS and NMR data, as well as by comparison with literature data. The methanolic extract of leaves from E. pulchrum inhibited the growth of the Bacillus subtilis CCT 0516, Escherichia coli ATCC 2536, Pseudomonas aeruginosa ATCC 8027, P. aeruginosa ATCC 25619, Staphylococcus aureus ATCC 6538, S. aureus ATCC 25925, Streptococcus sanguinis ATCC 15300, S. salivarius ATCC 7073, S. mutans ATCC 25175 and Streptococcus ATCC. S. aureus ATCC 25925 was the most sensitive among the other S. sanguinis while S. salivarius proved the most resistant.
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constituintes quimicos e atividade farmacologica de erythroxylum pulchrum st hil Erythroxylaceae
2013Co-Authors: Camila Holanda De ,albuquerqueAbstract:Os produtos naturais representam uma rica fonte de compostos biologicamente ativos e sao um exemplo de diversidade molecular, com reconhecido potencial na descoberta e desenvolvimento de novos medicamentos. Erythroxylum pulchrum, (Erythroxylaceae) e exclusiva da flora brasileira, com distribuicao no Nordeste e Sudeste do pais, so foi encontrada na Paraiba em uma area do Pico do Jabre PB. Uma exsicata encontra-se depositada no Herbario Prof. Lauro Pires Xavier (JPB), sob o n° 4947. Neste estudo fitoquimico, as partes aereas secas e pulverizadas foram submetidas a uma extracao com metanol e em seguida, particionados. A fase acetato de etila foi submetida a cromatografia liquida de media pressao. Desta maneira, foi possivel isolar quatro flavonoides: epicatequina, quercetina-3-O-α-L-raminosideo, ombuin-3- rutinosideo e ombuin-3-rutinosideo-5-glicosideo. A fase hexânica tambem foi submetida a cromatografia liquida de media pressao, em que foi possivel isolar um terpenoide lupeol e um esteroide β-sitosterol. Essas substâncias tiveram sua identificacao estrutural baseada na analise de dados espectrais de IV, EM, RMN 1H e 13C, incluindo tecnicas bidimensionais homonucleares e heteronucleares, alem de comparacao com dados da literatura. Foi avaliado tambem, o efeito antibacteriano do extrato metanolico bruto de Erythroxylum pulchrum frente a cepas de bacterias de importância clinica, determinando a concentracao inibitoria minima do extrato metanolico para cada linhagem de bacteria testada pela tecnica de microdiluicao. Assim, o extrato inibiu o crescimento das linhagens bacterianas de Bacillus subtilis CCT 0516, Escherichia coli ATCC 2536, Pseudomonas aeruginosa ATCC 8027, Pseudomonas aeruginosa ATCC 25619, Staphylococcus aureus ATCC 6538, Staphylococcus aureus ATCC 25925, Streptococcus sanguineos, Streptococcus salivares, Streptococcus mutans e Streptococcus ATCC. No entanto, a especie Staphylococcus aureus ATCC 25925 foi a mais sensivel, e especies as Streptococcus sanguineos e Streptococcus salivares foram as mais resistentes a acao antibacteriana do extrato metanolico bruto. Os resultados obtidos neste trabalho contribuiram para o conhecimento fitoquimico e farmacologico de Erythroxylum pulchrum e para a o conhecimento quimiotaxonomico do genero Erythroxylum e da familia Erythroxylaceae.
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Constituintes químicos e atividade farmacológica de Erythroxylum pulchrum St. Hil. (Erythroxylaceae)
2013Co-Authors: Camila Holanda De ,albuquerqueAbstract:Os produtos naturais representam uma rica fonte de compostos biologicamente ativos e são um exemplo de diversidade molecular, com reconhecido potencial na descoberta e desenvolvimento de novos medicamentos. Erythroxylum pulchrum, (Erythroxylaceae) é exclusiva da flora brasileira, com distribuição no Nordeste e Sudeste do país, só foi encontrada na Paraíba em uma área do Pico do Jabre PB. Uma exsicata encontra-se depositada no Herbário Prof. Lauro Pires Xavier (JPB), sob o n° 4947. Neste estudo fitoquímico, as partes aéreas secas e pulverizadas foram submetidas a uma extração com metanol e em seguida, particionados. A fase acetato de etila foi submetida à cromatografia líquida de media pressão. Desta maneira, foi possível isolar quatro flavonoides: epicatequina, quercetina-3-O-α-L-raminosídeo, ombuin-3- rutinosídeo e ombuin-3-rutinosideo-5-glicosídeo. A fase hexânica também foi submetida à cromatografia líquida de media pressão, em que foi possível isolar um terpenoide lupeol e um esteróide β-sitosterol. Essas substâncias tiveram sua identificação estrutural baseada na análise de dados espectrais de IV, EM, RMN 1H e 13C, incluindo técnicas bidimensionais homonucleares e heteronucleares, além de comparação com dados da literatura. Foi avaliado também, o efeito antibacteriano do extrato metanólico bruto de Erythroxylum pulchrum frente a cepas de bactérias de importância clínica, determinando a concentração inibitória mínima do extrato metanólico para cada linhagem de bactéria testada pela técnica de microdiluição. Assim, o extrato inibiu o crescimento das linhagens bacterianas de Bacillus subtilis CCT 0516, Escherichia coli ATCC 2536, Pseudomonas aeruginosa ATCC 8027, Pseudomonas aeruginosa ATCC 25619, Staphylococcus aureus ATCC 6538, Staphylococcus aureus ATCC 25925, Streptococcus sanguíneos, Streptococcus salivares, Streptococcus mutans e Streptococcus ATCC. No entanto, a espécie Staphylococcus aureus ATCC 25925 foi a mais sensível, e espécies as Streptococcus sanguíneos e Streptococcus salivares foram as mais resistentes á ação antibacteriana do extrato metanólico bruto. Os resultados obtidos neste trabalho contribuíram para o conhecimento fitoquímico e farmacológico de Erythroxylum pulchrum e para a o conhecimento quimiotaxonômico do gênero Erythroxylum e da família Erythroxylaceae.The natural products represent a rich source of bioactive compounds and are an example of molecular diversity, with a well-known potential on the discovery and development of new drugs. Erythroxylum pulchrum, (Erythroxylaceae) is an exclusive species from the brazilian flora, distributed on the northeast and southeast regions of the country; which can be found in Paraíba in a particular area of Pico do Jabre PB . A voucher specimen is deposited at the Professor Lauro Pires Xavier (JPB) herbarium with the code 4947. On this phytochemical study the dried powder of the aerial parts was submitted to an extraction with methanol, followed by partition. The ethyl acetate fraction was submitted to a Medium Pressure Liquid Chromatography. Therefore, it was possible to identify four flavonoids: epicatechin, quercetin-3-O-α-Lrhamnoside, ombuin-3-rutinosideand ombuin-3-rutinoside-5-glucoside. The hexanic fraction was also submitted to a Medium Pressure Liquid Chromatography which led to the identification of one terpenoid - lupeol and one steroid - β- sitosterol. These substances were identified by analysis of data obtained from spectroscopic methods such as infrared, mass spectrometry and NMR of 1H and 13C, with the aid of two dimensional techniques, besides comparison with literature data. It was also evaluated the antimicrobial activity from its crude extract against bacterial strains of clinical matter by measuring the minimum inhibitory concentration for each bacterial strain tested by the microdilution assay. So, the crude extract inhibited the growth of the following bacterial strains: Bacillus subtilis CCT 0516, Escherichia coli ATCC 2536, Pseudomonas aeruginosaA TCC 8027, Pseudomonas aeruginosa ATCC 25619, Staphylococcus aureusATCC 6538, Staphylococcus aureusATCC 25925, Streptococcus sanguíneos, Streptococcus salivares, Streptococcus mutansand Streptococcus ATCC. However, the genus Staphylococcus aureus ATCC 25925 was the most sensible, but on the other hand, the species Streptococcus sanguíneos e Streptococcus salivares was the most resistant against the antimicrobial effect of the crude extract. The results obtained on this research contributed to the phytochemical and pharmacology study of Erythroxylum pulchrum and to the chemotaxonomic knowledge of the genus Erythroxylum, as well as the Erythroxylaceae family
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Constituintes químicos e atividade farmacológica de Erythroxylum pulchrum St. Hil. (Erythroxylaceae)
2013Co-Authors: Camila Holanda De ,albuquerqueAbstract:The natural products represent a rich source of bioactive compounds and are an example of molecular diversity, with a well-known potential on the discovery and development of new drugs. Erythroxylum pulchrum, (Erythroxylaceae) is an exclusive species from the brazilian flora, distributed on the northeast and southeast regions of the country; which can be found in Paraíba in a particular area of Pico do Jabre PB . A voucher specimen is deposited at the Professor Lauro Pires Xavier (JPB) herbarium with the code 4947. On this phytochemical study the dried powder of the aerial parts was submitted to an extraction with methanol, followed by partition. The ethyl acetate fraction was submitted to a Medium Pressure Liquid Chromatography. Therefore, it was possible to identify four flavonoids: epicatechin, quercetin-3-O-α-Lrhamnoside, ombuin-3-rutinosideand ombuin-3-rutinoside-5-glucoside. The hexanic fraction was also submitted to a Medium Pressure Liquid Chromatography which led to the identification of one terpenoid - lupeol and one steroid - β- sitosterol. These substances were identified by analysis of data obtained from spectroscopic methods such as infrared, mass spectrometry and NMR of 1H and 13C, with the aid of two dimensional techniques, besides comparison with literature data. It was also evaluated the antimicrobial activity from its crude extract against bacterial strains of clinical matter by measuring the minimum inhibitory concentration for each bacterial strain tested by the microdilution assay. So, the crude extract inhibited the growth of the following bacterial strains: Bacillus subtilis CCT 0516, Escherichia coli ATCC 2536, Pseudomonas aeruginosaA TCC 8027, Pseudomonas aeruginosa ATCC 25619, Staphylococcus aureusATCC 6538, Staphylococcus aureusATCC 25925, Streptococcus sanguíneos, Streptococcus salivares, Streptococcus mutansand Streptococcus ATCC. However, the genus Staphylococcus aureus ATCC 25925 was the most sensible, but on the other hand, the species Streptococcus sanguíneos e Streptococcus salivares was the most resistant against the antimicrobial effect of the crude extract. The results obtained on this research contributed to the phytochemical and pharmacology study of Erythroxylum pulchrum and to the chemotaxonomic knowledge of the genus Erythroxylum, as well as the Erythroxylaceae family.Coordenação de Aperfeiçoamento de Pessoal de Nível Superior - CAPESOs produtos naturais representam uma rica fonte de compostos biologicamente ativos e são um exemplo de diversidade molecular, com reconhecido potencial na descoberta e desenvolvimento de novos medicamentos. Erythroxylum pulchrum, (Erythroxylaceae) é exclusiva da flora brasileira, com distribuição no Nordeste e Sudeste do país, só foi encontrada na Paraíba em uma área do Pico do Jabre PB. Uma exsicata encontra-se depositada no Herbário Prof. Lauro Pires Xavier (JPB), sob o n° 4947. Neste estudo fitoquímico, as partes aéreas secas e pulverizadas foram submetidas a uma extração com metanol e em seguida, particionados. A fase acetato de etila foi submetida à cromatografia líquida de media pressão. Desta maneira, foi possível isolar quatro flavonoides: epicatequina, quercetina-3-O-α-L-raminosídeo, ombuin-3- rutinosídeo e ombuin-3-rutinosideo-5-glicosídeo. A fase hexânica também foi submetida à cromatografia líquida de media pressão, em que foi possível isolar um terpenoide lupeol e um esteróide β-sitosterol. Essas substâncias tiveram sua identificação estrutural baseada na análise de dados espectrais de IV, EM, RMN 1H e 13C, incluindo técnicas bidimensionais homonucleares e heteronucleares, além de comparação com dados da literatura. Foi avaliado também, o efeito antibacteriano do extrato metanólico bruto de Erythroxylum pulchrum frente a cepas de bactérias de importância clínica, determinando a concentração inibitória mínima do extrato metanólico para cada linhagem de bactéria testada pela técnica de microdiluição. Assim, o extrato inibiu o crescimento das linhagens bacterianas de Bacillus subtilis CCT 0516, Escherichia coli ATCC 2536, Pseudomonas aeruginosa ATCC 8027, Pseudomonas aeruginosa ATCC 25619, Staphylococcus aureus ATCC 6538, Staphylococcus aureus ATCC 25925, Streptococcus sanguíneos, Streptococcus salivares, Streptococcus mutans e Streptococcus ATCC. No entanto, a espécie Staphylococcus aureus ATCC 25925 foi a mais sensível, e espécies as Streptococcus sanguíneos e Streptococcus salivares foram as mais resistentes á ação antibacteriana do extrato metanólico bruto. Os resultados obtidos neste trabalho contribuíram para o conhecimento fitoquímico e farmacológico de Erythroxylum pulchrum e para a o conhecimento quimiotaxonômico do gênero Erythroxylum e da família Erythroxylaceae
John C Dauria - One of the best experts on this subject based on the ideXlab platform.
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plant tropane alkaloid biosynthesis evolved independently in the solanaceae and Erythroxylaceae
2012Co-Authors: Jan Jirschitzka, Gregor W Schmidt, Michael Reichelt, Bernd Schneider, Jonathan Gershenzon, John C DauriaAbstract:The pharmacologically important tropane alkaloids have a scattered distribution among angiosperm families, like many other groups of secondary metabolites. To determine whether tropane alkaloids have evolved repeatedly in different lineages or arise from an ancestral pathway that has been lost in most lines, we investigated the tropinone-reduction step of their biosynthesis. In species of the Solanaceae, which produce compounds such as atropine and scopolamine, this reaction is known to be catalyzed by enzymes of the short-chain dehydrogenase/reductase family. However, in Erythroxylum coca (Erythroxylaceae), which accumulates cocaine and other tropane alkaloids, no proteins of the short-chain dehydrogenase/reductase family were found that could catalyze this reaction. Instead, purification of E. coca tropinone-reduction activity and cloning of the corresponding gene revealed that a protein of the aldo-keto reductase family carries out this reaction in E. coca. This protein, designated methylecgonone reductase, converts methylecgonone to methylecgonine, the penultimate step in cocaine biosynthesis. The protein has highest sequence similarity to other aldo-keto reductases, such as chalcone reductase, an enzyme of flavonoid biosynthesis, and codeinone reductase, an enzyme of morphine alkaloid biosynthesis. Methylecgonone reductase reduces methylecgonone (2-carbomethoxy-3-tropinone) stereospecifically to 2-carbomethoxy-3β-tropine (methylecgonine), and has its highest activity, protein level, and gene transcript level in young, expanding leaves of E. coca. This enzyme is not found at all in root tissues, which are the site of tropane alkaloid biosynthesis in the Solanaceae. This evidence supports the theory that the ability to produce tropane alkaloids has arisen more than once during the evolution of the angiosperms.
Michael Reichelt - One of the best experts on this subject based on the ideXlab platform.
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plant tropane alkaloid biosynthesis evolved independently in the solanaceae and Erythroxylaceae
2012Co-Authors: Jan Jirschitzka, Gregor W Schmidt, Michael Reichelt, Bernd Schneider, Jonathan Gershenzon, John C DauriaAbstract:The pharmacologically important tropane alkaloids have a scattered distribution among angiosperm families, like many other groups of secondary metabolites. To determine whether tropane alkaloids have evolved repeatedly in different lineages or arise from an ancestral pathway that has been lost in most lines, we investigated the tropinone-reduction step of their biosynthesis. In species of the Solanaceae, which produce compounds such as atropine and scopolamine, this reaction is known to be catalyzed by enzymes of the short-chain dehydrogenase/reductase family. However, in Erythroxylum coca (Erythroxylaceae), which accumulates cocaine and other tropane alkaloids, no proteins of the short-chain dehydrogenase/reductase family were found that could catalyze this reaction. Instead, purification of E. coca tropinone-reduction activity and cloning of the corresponding gene revealed that a protein of the aldo-keto reductase family carries out this reaction in E. coca. This protein, designated methylecgonone reductase, converts methylecgonone to methylecgonine, the penultimate step in cocaine biosynthesis. The protein has highest sequence similarity to other aldo-keto reductases, such as chalcone reductase, an enzyme of flavonoid biosynthesis, and codeinone reductase, an enzyme of morphine alkaloid biosynthesis. Methylecgonone reductase reduces methylecgonone (2-carbomethoxy-3-tropinone) stereospecifically to 2-carbomethoxy-3β-tropine (methylecgonine), and has its highest activity, protein level, and gene transcript level in young, expanding leaves of E. coca. This enzyme is not found at all in root tissues, which are the site of tropane alkaloid biosynthesis in the Solanaceae. This evidence supports the theory that the ability to produce tropane alkaloids has arisen more than once during the evolution of the angiosperms.
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Plant tropane alkaloid biosynthesis evolved independently in the Solanaceae and Erythroxylaceae
2012Co-Authors: Jan Jirschitzka, Gregor W Schmidt, Michael Reichelt, Bernd Schneider, Jonathan Gershenzon, John C. D’auriaAbstract:The pharmacologically important tropane alkaloids have a scattered distribution among angiosperm families, like many other groups of secondary metabolites. To determine whether tropane alkaloids have evolved repeatedly in different lineages or arise from an ancestral pathway that has been lost in most lines, we investigated the tropinone-reduction step of their biosynthesis. In species of the Solanaceae, which produce compounds such as atropine and scopolamine, this reaction is known to be catalyzed by enzymes of the short-chain dehydrogenase/reductase family. However, in Erythroxylum coca (Erythroxylaceae), which accumulates cocaine and other tropane alkaloids, no proteins of the short-chain dehydrogenase/reductase family were found that could catalyze this reaction. Instead, purification of E. coca tropinone-reduction activity and cloning of the corresponding gene revealed that a protein of the aldo-keto reductase family carries out this reaction in E. coca. This protein, designated methylecgonone reductase, converts methylecgonone to methylecgonine, the penultimate step in cocaine biosynthesis. The protein has highest sequence similarity to other aldo-keto reductases, such as chalcone reductase, an enzyme of flavonoid biosynthesis, and codeinone reductase, an enzyme of morphine alkaloid biosynthesis. Methylecgonone reductase reduces methylecgonone (2-carbomethoxy-3-tropinone) stereospecifically to 2-carbomethoxy-3β-tropine (methylecgonine), and has its highest activity, protein level, and gene transcript level in young, expanding leaves of E. coca. This enzyme is not found at all in root tissues, which are the site of tropane alkaloid biosynthesis in the Solanaceae. This evidence supports the theory that the ability to produce tropane alkaloids has arisen more than once during the evolution of the angiosperms.