Hxt13, Hxt15, Hxt16 and Hxt17 from Saccharomyces cerevisiae represent a novel type of polyol transporters.
Hxt13, Hxt15, Hxt16 and Hxt17 from Saccharomyces cerevisiae represent a novel type of polyol transporters.
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DOI：
10.1038/srep23502
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发表时间：
2016-03-21
影响因子：
4.6
通讯作者：
Oreb M
中科院分区：
文献类型：
--
作者：
Jordan P;Choe JY;Boles E;Oreb M
S. cerevisae编码至少20种己糖转运蛋白样蛋白。尽管进行了广泛的研究，Hxt 8-Hxt 17的功能仍然不清楚。在这里，我们表明，Hxt 13，Hxt 15，Hxt 16和Hxt 17运输两个主要的己糖醇在自然界中，甘露醇和山梨醇，具有中等的亲和力，由一个促进机制。此外，Hxt 11和Hxt 15能够运输木糖醇，一种衍生自木糖的五碳多元醇，木糖是木质纤维素生物质中最丰富的戊糖。Hxt 11、Hxt 13、Hxt 15、Hxt 16和Hxt 17在遗传上和功能上不同于已知的多元醇转运蛋白。基于多元醇与转运蛋白同源模型的对接，我们提出了其活性位点的结构。此外，我们确定了动力学参数的甘露醇和山梨醇脱氢酶编码的酵母基因组中，表明它们之间的甘露醇和山梨醇的区别，以更高的程度比转运。
The genome of S. cerevisae encodes at least twenty hexose transporter-like proteins. Despite extensive research, the functions of Hxt8-Hxt17 have remained poorly defined. Here, we show that Hxt13, Hxt15, Hxt16 and Hxt17 transport two major hexitols in nature, mannitol and sorbitol, with moderate affinities, by a facilitative mechanism. Moreover, Hxt11 and Hxt15 are capable of transporting xylitol, a five-carbon polyol derived from xylose, the most abundant pentose in lignocellulosic biomass. Hxt11, Hxt13, Hxt15, Hxt16 and Hxt17 are phylogenetically and functionally distinct from known polyol transporters. Based on docking of polyols to homology models of transporters, we propose the architecture of their active site. In addition, we determined the kinetic parameters of mannitol and sorbitol dehydrogenases encoded in the yeast genome, showing that they discriminate between mannitol and sorbitol to a much higher degree than the transporters.