Cloning of the cytochrome p450 reductase (crtR) gene and its involvement in the astaxanthin biosynthesis of Xanthophyllomyces dendrorhous
Cloning of the cytochrome p450 reductase (crtR) gene and its involvement in the astaxanthin biosynthesis of Xanthophyllomyces dendrorhous
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DOI：
10.1186/1471-2180-8-169
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发表时间：
2008-10-06
期刊：
影响因子：
4.2
通讯作者：
Cifuentes, Victor
中科院分区：
文献类型：
--
作者：
Alcaino, Jennifer;Barahona, Salvador;Cifuentes, Victor
背景：酵母Xanthophyllomycesdendronhous合成虾青素，一种具有高度商业价值的类胡萝卜素。在这种生物体中提出的生物合成路线是异戊烯焦磷酸（IPP）->香叶基蜡基焦磷酸（GGPP）->八氢番茄红素->番茄红素-> β-胡萝卜素->虾青素。最近，已经公开了β-胡萝卜素转化为虾青素仅需要一种酶，即由crtS基因编码的虾青素合成酶或CrtS。该酶属于细胞色素P450蛋白家族。结果：在这项工作中，从X中分离到了crtR基因。树状酵母，其编码细胞色素P450还原酶（CPR），其为CrtS提供底物氧化所必需的电子。我们确定了crtR基因的结构组织及其在酵母电泳核型中的位置。通过缺失crtR基因并插入潮霉素B抗性盒获得两个转化体CBSTr和T13。转化体的类胡萝卜素组成相对于野生型菌株改变。CBSTr形成黄色菌落，因为它不能产生虾青素，因此积累β-胡萝卜素。T13形成苍白菌落是因为其虾青素含量减少而β-胡萝卜素含量增加。dendrorhous需要一种新的基因crtR，用于将β-胡萝卜素转化为虾青素。
Background: The yeast Xanthophyllomyces dendrorhous synthesizes astaxanthin, a carotenoid with high commercial interest. The proposed biosynthetic route in this organism is isopentenylpyrophosphate (IPP) -> geranyleranyl pyrophosphate (GGPP) -> phytoene -> lycopene -> beta-carotene -> astaxanthin. Recently, it has been published that the conversion of beta-carotene into astaxanthin requires only one enzyme, astaxanthin synthase or CrtS, encoded by crtS gene. This enzyme belongs to the cytochrome P450 protein family.Results: In this work, a crtR gene was isolated from X. dendrorhous yeast, which encodes a cytochrome P450 reductase (CPR) that provides CrtS with the necessary electrons for substrate oxygenation. We determined the structural organization of the crtR gene and its location in the yeast electrophoretic karyotype. Two transformants, CBSTr and T13, were obtained by deleting the crtR gene and inserting a hygromycin B resistance cassette. The carotenoid composition of the transformants was altered in relation to the wild type strain. CBSTr forms yellow colonies because it is unable to produce astaxanthin, hence accumulating beta-carotene. T13 forms pale colonies because its astaxanthin content is reduced and its beta-carotene content is increased.Conclusion: In addition to the crtS gene, X. dendrorhous requires a novel gene, crtR, for the conversion of beta-carotene to astaxanthin.