Molecular Characterization and Functional Analysis of Cytochrome b5 Reductase (CBR) Encoding Genes from the Carotenogenic Yeast Xanthophyllomyces dendrorhous
Author
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Gutiérrez, María Soledad
Author
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Rojas Garrido, María Cecilia
Author
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Sepúlveda, Dionisia
Author
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Baeza Cancino, Marcelo
Author
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Cifuentes Guzmán, Víctor
Author
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Alcaíno Gorman, Jennifer
Admission date
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2015-12-22T01:40:40Z
Available date
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2015-12-22T01:40:40Z
Publication date
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2015
Cita de ítem
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PLoS One Volumen: 10 Número: 10 Número de artículo: e0140424 (2015)
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Identifier
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DOI: 10.1371/journal.pone.0140424
Identifier
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https://repositorio.uchile.cl/handle/2250/135876
General note
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Artículo de publicación ISI
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Abstract
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The eukaryotic microsomal cytochrome P450 systems consist of a cytochrome P450 enzyme (P450) and a cytochrome P450 redox partner, which generally is a cytochrome P450 reductase (CPR) that supplies electrons from NADPH. However, alternative electron donors may exist such as cytochrome b5 reductase and cytochrome b5 (CBR and CYB5, respectively) via, which is NADH-dependent and are also anchored to the endoplasmic reticulum. In the carotenogenic yeast Xanthophyllomyces dendrorhous, three P450-encoding genes have been described: crtS is involved in carotenogenesis and the CYP51 and CYP61 genes are both implicated in ergosterol biosynthesis. This yeast has a single CPR (encoded by the crtR gene), and a crtR(-) mutant does not produce astaxanthin. Considering that this mutant is viable, the existence of alternative cytochrome P450 electron donors like CBR and CYB5 could operate in this yeast. The aim of this work was to characterize the X. dendrorhous CBR encoding gene and to study its involvement in P450 reactions in ergosterol and carotenoid biosynthesis. Two CBRs genes were identified (CBR.1 and CBR.2), and deletion mutants were constructed. The two mutants and the wild-type strain showed similar sterol production, with ergosterol being the main sterol produced. The crtR(-) mutant strain produced a lower proportion of ergosterol than did the parental strain. These results indicate that even though one of the two CBR genes could be involved in ergosterol biosynthesis, crtR complements their absence in the cbr(-) mutant strains, at least for ergosterol production. The higher NADH-dependent cytochrome c reductase activity together with the higher transcript levels of CBR.1 and CYB5 in the crtR(-) mutant as well as the lower NADH-dependent activity in CBS-cbr.1(-) strongly suggest that CBR. 1-CYB5 via participates as an alternative electron donor pathway for P450 enzymes involved in ergosterol biosynthesis in X. dendrorhous.
en_US
Patrocinador
dc.description.sponsorship
Fondo Nacional de Desarrollo Científico y Tecnológico
11121200
Comisión Nacional de Investigación Científica y Tecnológica
21130807
Molecular Characterization and Functional Analysis of Cytochrome b5 Reductase (CBR) Encoding Genes from the Carotenogenic Yeast Xanthophyllomyces dendrorhous