Characterization and evolution of xylose isomerase screened from the bovine rumen metagenome in Saccharomyces cerevisiae
Characterization and evolution of xylose isomerase screened from the bovine rumen metagenome in Saccharomyces cerevisiae
复制标题
从酿酒酵母牛瘤胃宏基因组中筛选的木糖异构酶的表征和进化
DOI：
10.1016/j.jbiosc.2015.05.014
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发表时间：
2016-02-01
影响因子：
2.8
通讯作者：
Bao, Xiaoming
中科院分区：
文献类型：
--
作者：
Hou, Jin;Shen, Yu;Bao, Xiaoming
将木质纤维材料中丰富的木糖转化为可行的产品将产生经济效益。木糖异构酶(XI)基因的异源表达被认为是在酿酒酵母中建立木糖代谢途径的直接和有效的策略。然而，在酿酒酵母中，只有有限的木糖A在功能上表达，并能够驱动有效的木糖消耗。本研究从牛瘤胃元基因组文库中筛选出Ru-xylA(Ru代表瘤胃)，在酿酒酵母中进行了功能性表达，其酶活为1.31U mg(-1)蛋白。这是一种在酿酒酵母中表现出高活性水平的XI的新来源。该酶的活性与Piromyces sp.相当。XL，通过诱变和着丝粒筛选进一步提高了Ru-XI的活性。分离到一个含有两个突变(K11T/D220V)的变异体，其酶活性提高了68%。我们的工作发现了一种新的木糖异构酶，它可以在酿酒酵母中进行功能性表达，并通过诱变获得更高的XI酶活性。(C)2015年，日本生物技术学会。版权所有。
The conversion of abundant levels of xylose in lignocellulosic materials into viable products would generate economic benefits. The heterologous expression of the xylose isomerase (XI) gene is considered a direct and effective strategy for establishing the xylose metabolic pathway in Saccharomyces cerevisiae. However, only limited sources of xylA are functionally expressed in S. cerevisiae and are capable of driving effective xylose consumption. In this study, Ru-xylA (where Ru represents the rumen), which was screened from the contents of the bovine rumen metagenomic library, was functionally expressed in S. cerevisiae, and the enzyme activity was 1.31 U mg(-1) protein. This is a new source of XI that can exhibit high activity levels in S. cerevisiae. The activity of this enzyme is comparable to those of the Piromyces sp. XL Then, the Ru-XI activity was further improved through mutagenesis and growth-based screening in a centromeric plasmid. A variant containing two mutations (K11T/D220V) that exhibited a 68% increase in enzyme activity was isolated. Our work identified a new xylose isomerase that can be functionally expressed in S. cerevisiae and results in a higher XI enzyme activity through mutagenesis. (C) 2015, The Society for Biotechnology, Japan. All rights reserved.