The need to restructure the world’s energy matrix based on fossil fuels and mitigate greenhouse gas emissions stimulated the development of new biobased technologies for renewable energy. One promising and cleaner alternative is the use of second-generation (2G) fuels, produced from lignocellulosic biomass sugars. A major challenge on 2G technologies establishment is the inefficient assimilation of the five-carbon sugar xylose by engineered Saccharomyces cerevisiae strains, increasing fermentation time. The uptake of xylose across the plasma membrane is a critical limiting step and the budding yeast S. cerevisiae is not designed with a broad transport system and regulatory mechanisms to assimilate xylose in a wide range of concentrations present in 2G processes. Assessing diverse microbiomes such as the digestive tract of plague insects and several decayed lignocellulosic biomasses, we isolated several yeast species capable of using xylose. Comparative fermentations selected the yeast Candida sojae as a potential source of high-affinity transporters. Comparative genomic analysis elects four potential xylose transporters whose properties were evaluated in the transporter null EBY.VW4000 strain carrying the xylose-utilizing pathway integrated into the genome. While the traditional xylose transporter Gxf1 allows an improved growth at lower concentrations (10 g/L), strains containing Cs3894 and Cs4130 show opposite responses with superior xylose uptake at higher concentrations (up to 50 g/L). Docking and normal mode analysis of Cs4130 and Gxf1 variants pointed out important residues related to xylose transport, identifying key differences regarding substrate translocation comparing both transporters. Considering that xylose concentrations in second-generation hydrolysates can reach high values in several designed processes, Cs4130 is a promising novel candidate for xylose uptake. Here, we demonstrate a novel eukaryotic molecular transporter protein that improves growth at high xylose concentrations and can be used as a promising target towards engineering efficient pentose utilization in yeast.

中文翻译：

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新型木糖转运蛋白 Cs4130 在高木糖浓度下扩展了重组酿酒酵母菌株的糖摄取库。

重组基于化石燃料的世界能源矩阵和减少温室气体排放的需求刺激了新的生物基可再生能源技术的发展。一种有前途且更清洁的替代方案是使用由木质纤维素生物质糖生产的第二代 (2G) 燃料。2G技术建立的一个主要挑战是工程酿酒酵母菌株对五碳糖木糖的低效同化，增加了发酵时间。跨质膜摄取木糖是一个关键的限制步骤，并且出芽酵母 S. cerevisiae 没有设计具有广泛的运输系统和调节机制来同化 2G 过程中存在的各种浓度的木糖。通过评估不同的微生物群落，例如瘟疫昆虫的消化道和几种腐烂的木质纤维素生物质，我们分离出几种能够使用木糖的酵母菌。比较发酵选择酵母酱油念珠菌作为高亲和力转运蛋白的潜在来源。比较基因组分析选择了四种潜在的木糖转运蛋白，它们的特性在转运蛋白无效 EBY.VW4000 菌株中进行了评估，该菌株携带整合到基因组中的木糖利用途径。虽然传统的木糖转运蛋白 Gxf1 允许在较低浓度（10 g/L）下改善生长，但含有 Cs3894 和 Cs4130 的菌株表现出相反的反应，在较高浓度（高达 50 g/L）下具有出色的木糖摄取。Cs4130 和 Gxf1 变体的对接和正常模式分析指出了与木糖转运相关的重要残基，确定了比较两种转运蛋白的底物易位的关键差异。考虑到第二代水解产物中的木糖浓度在几个设计过程中可以达到很高的值，Cs4130 是一种很有前途的木糖吸收新候选物。在这里，我们展示了一种新型真核分子转运蛋白，它可以在高木糖浓度下改善生长，并且可以用作在酵母中设计高效戊糖利用的有希望的目标。Cs4130 是一种有前途的木糖吸收新候选物。在这里，我们展示了一种新型真核分子转运蛋白，它可以在高木糖浓度下改善生长，并且可以用作在酵母中设计高效戊糖利用的有希望的目标。Cs4130 是一种有前途的木糖吸收新候选物。在这里，我们展示了一种新型真核分子转运蛋白，它可以在高木糖浓度下改善生长，并且可以用作在酵母中设计高效戊糖利用的有希望的目标。