Plant progesterone 5β-reductase is not homologous to the animal enzyme. Molecular evolutionary characterization of P5βR from Digitalis purpurea

Gavidia, Isabel; Tarrı́o, Rosa; Rodrı́guez-Trelles, Francisco; Pérez‐Bermúdez, Pedro; Seitz, Hanns Ulrich

doi:10.1016/j.phytochem.2006.11.019

Cited by 45 publications

(78 citation statements)

References 52 publications

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“…5 for a selection of proteins). The proteins that can be identified are from prokaryotes as well as from eukaryotes and are present either in plants or bacteria but strikingly not in animals (21). The exact function of many of these proteins is not yet clear as they have only tentatively been classified as oxidoreductases or epimerases in data bases.…”

Section: ) (44)mentioning

confidence: 99%

“…Based on sequence alignments, 5␤-POR from Digitalis plants has been predicted to be an SDR family member (5,21). This is in contrast to mammalian steroid 5␤-reductase, which is a member of the AKR family (22).…”

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confidence: 99%

“…Plant 5␤-POR shares the typical NADPH/NADH-binding sequence motifs with other SDRs (18), but intriguingly, none of the sequence motifs that cluster around the substrate-binding site and that contain the catalytically important residues are conserved. The sequence motif that displays the conserved active site serine residue in SDRs, namely GXXXXXSS (or SSXXXXG in some SDRs) (10,18), is missing in 5␤-POR (5,21). Also, the sequence motif YXXXK (or YXXMXXXK) (10,18) that displays the active site tyrosine and lysine residue is absent, and a conserved NFYYXXED motif can be found instead (5,21).…”

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confidence: 99%

“…The sequence motif that displays the conserved active site serine residue in SDRs, namely GXXXXXSS (or SSXXXXG in some SDRs) (10,18), is missing in 5␤-POR (5,21). Also, the sequence motif YXXXK (or YXXMXXXK) (10,18) that displays the active site tyrosine and lysine residue is absent, and a conserved NFYYXXED motif can be found instead (5,21). Although it has been suggested that one of the tyrosines in this motif corresponds to the typical SDR active site tyrosine, it is not possible to locate the additionally required lysine residue in any of the adjacent sequence segments.…”

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confidence: 99%

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The Crystal Structure of Progesterone 5β-Reductase from Digitalis lanata Defines a Novel Class of Short Chain Dehydrogenases/Reductases

Thorn

Egerer-Sieber

Jäger

et al. 2008

Journal of Biological Chemistry

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Progesterone 5␤-reductase (5␤-POR) catalyzes the stereospecific reduction of progesterone to 5␤-pregnane-3,20-dione and is a key enzyme in the biosynthetic pathway of cardenolides in Digitalis (foxglove) plants. Sequence considerations suggested that 5␤-POR is a member of the short chain dehydrogenase/reductase (SDR) family of proteins but at the same time revealed that the sequence motifs that in standard SDRs contain the catalytically important residues are missing. Here we present crystal structures of 5␤-POR from Digitalis lanata in complex with NADP ؉ at 2.3 Å and without cofactor bound at 2.4 Å resolution together with a model of a ternary complex consisting of 5␤-POR, NADP ؉ , and progesterone. Indeed, 5␤-POR displays the fold of an extended SDR. The architecture of the active site is, however, unprecedented because none of the standard catalytic residues are structurally conserved. A tyrosine (Tyr-179) and a lysine residue (Lys-147) are present in the active site, but they are displayed from novel positions and are part of novel sequence motifs. Mutating Tyr-179 to either alanine or phenylalanine completely abolishes the enzymatic activity. We propose that the distinct topology reflects the fact that 5␤-POR reduces a conjugated double bond in a steroid substrate via a 1-4 addition mechanism and that this requires a repositioning of the catalytically important residues. Our observation that the sequence motifs that line the active site are conserved in a number of bacterial and plant enzymes of yet unknown function leads us to the proposition that 5␤-POR defines a novel class of SDRs.The beneficial effects of cardenolides, also known as cardiac glycosides or cardiotonic steroids, are well documented, and they have been applied for the treatment of cardiac insufficiencies for centuries (1-3). On a molecular level, these steroids are potent inhibitors of the sodium/potassium pump (Na ϩ /K ϩ -ATPase) that is present in almost all cells in higher organisms (4). Digitalis plants are still the major source for cardenolides, and as a step in the biosynthetic pathway, the Digitalis enzyme progesterone 5␤-reductase (5␤-POR) 2 catalyzes the stereospecific NADPH-dependent reduction of the ⌬ 4 -double bond in progesterone to 5␤-pregnane-3,20-dione. Because all Digitalis cardenolides share the characteristic 5␤-configuration, the enzyme 5␤-POR catalyzes a central step during their biosynthesis (5-7).NADH/NADPH-dependent reductases as well as the related dehydrogenases, dehydratases, and epimerases can be classified into two major protein families: the (␣/␤) 8 -barrel containing aldo-keto-reductases (AKRs) (8) and the Rossman fold containing short chain dehydrogenases/reductases (SDRs) (9 -11). Additional families such as the long and medium chain dehydrogenases/reductases are related to SDRs because they share with the latter the dinucleotide-binding double Rossman fold (12)(13)(14). SDRs are about 250 residues long and form a large family with over 2000 members (15). Because their central feature consists of an all-p...

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Section: ) (44)mentioning

confidence: 99%

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confidence: 99%

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confidence: 99%

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confidence: 99%

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The Crystal Structure of Progesterone 5β-Reductase from Digitalis lanata Defines a Novel Class of Short Chain Dehydrogenases/Reductases

Thorn

Egerer-Sieber

Jäger

et al. 2008

Journal of Biological Chemistry

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“…Steroids may serve as an intermediate for the biosynthesis of downstream secondary natural products and it is believed to be a biosynthetic precursor for cardenolides in plants 39 . Independent of their function, the presence of steroids in practically every organism suggests that they have a powerful role in chemosystematics 40 . Seaweeds known as medicinal, are rich in secondary metabolites which includes alkaloids, glycosides, phenols, flavonoids, tannins, saponins, steroids, related active metabolites are of great medicinal value and have been extensively used in the drug and pharmaceutical industry.…”

Section: Discussionmentioning

confidence: 99%

Phytochemical Studies on Laurencia Obtusa (Hudson) Lamourux

Antonisamy

Babu

Janakiraman

et al. 2012

Int J of Biomed & Adv Res

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Aim: The present study was aimed to explore the phytochemical constituents present in Laurencia obtusa collected from Tamil Nadu, South India. Methods: Phytochemical screening of different extracts was carried out using the standard procedure and the results were illustrated. Results: Steroids show the maximum (4/6) presence in acetone, benzene, chloroform and petroleum ether extracts followed by alkaloids (3/6) in ethanol, acetone and chloroform extracts. The UV-Vis phytochemical profile of various extracts of L. obtusa was tabulated. The qualitative HPLC fingerprint profile of ethanolic extract of L. obtusa was selected at a wavelength of 254 nm due to sharpness of the peaks and proper baseline. The profile displayed one prominent peak at a retention time of 1.953 min and some moderate peaks were observed at a retention time of 3.000, 2.570 and 2.467 min respectively. Conclusion:The present studies on L. obtusa produced novel phytochemical markers in standardization as useful analytical tools to check not only the quality of the powder but also the presence of adulterants in ayurvedic drugs.

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Biochemistry of Sterols, Cardiac Glycosides, Brassinosteroids, Phytoecdysteroids and Steroid Saponins

Kreis

Müller‐Uri

2018

Annual Plant Reviews Online

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Phytosterols are synthesized via the mevalonate pathway of terpenoid formation and arise from the initial cyclization of 3 S ‐squalene‐2,3‐epoxide. Plant steroids are derived from sterols and comprise steroid saponins, steroid alkaloids, pregnanes, androstanes, estranes, ecdysteroids, withanolides and cardiac glycosides. The typical route of sterol and steroid biosynthesis follows the cycloartenol pathway, whereas the lanosterol route seems to be operative mainly in fungi and animals. It was demonstrated, however, that both sterol pathways can be operative in higher plants. Crucial steps in the conversion of cycloartenol/lanosterol to sterols are the events leading to the removal of the methyl groups at C‐4 and C‐14. Meanwhile, all steps in the sterol pathway have been elucidated and the respective enzymes/genes characterized. The biosynthetic pathway leading from phytosterol precursors to the cardiac glycosides – important compounds in the treatment of cardiac insufficiency in humans – was basically deduced from studies using radiolabelled precursors. The more recent identification and characterization of several enzymes/genes involved in pregnane and cardenolide metabolism, such as 3β‐hydroxysteroid dehydrogenase and progesterone 5β‐reductase, have further clarified the pathway. Brassinosteroids (BRs) are hydroxylated derivatives of cholestane and they are specific plant steroid hormones that are essential for normal plant development. The biosynthesis of BRs has mainly been studied in Arabidopsis thaliana . Many of the genes encoding biosynthetic enzymes have been cloned using mutants of Arabidopsis thaliana , pea, tomato and rice which revert to a wild‐type phenotype following treatment with exogenous BRs. Phytoecdysteroids are related in structure to the invertebrate steroid hormones. Their biological significance in plants is still under discussion. The understanding of the biosynthetic pathway(s) for phytoecdysteroids is very limited. Steroid saponins constitute a vast group of glycosides present almost exclusively in the monocotyledonous angiosperms, and occurring in only a few dicotyledonous families. As far as enzymatic and genetic aspects are concerned, the biosynthesis of steroid saponins (including the steroid alkaloids) has not been studied extensively. The withanolides are C 28 ‐steroids and biogenetically related to the steroid saponins in that they are derived from ergostane‐type sterols. These compounds appear to be specific for the Solanaceae and their biosynthesis has not yet been studied at the enzyme/gene level.

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Plant progesterone 5β-reductase is not homologous to the animal enzyme. Molecular evolutionary characterization of P5βR from Digitalis purpurea

Cited by 45 publications

References 52 publications

The Crystal Structure of Progesterone 5β-Reductase from Digitalis lanata Defines a Novel Class of Short Chain Dehydrogenases/Reductases

The Crystal Structure of Progesterone 5β-Reductase from Digitalis lanata Defines a Novel Class of Short Chain Dehydrogenases/Reductases

Phytochemical Studies on Laurencia Obtusa (Hudson) Lamourux

Biochemistry of Sterols, Cardiac Glycosides, Brassinosteroids, Phytoecdysteroids and Steroid Saponins

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