College of Life Sciences, Hebei University, Baoding, China.
Binzhou Polytechnic, Binzhou, Shandong, China.
J Basic Microbiol. 2019 May;59(5):542-551. doi: 10.1002/jobm.201800482. Epub 2019 Feb 12.
Xylulose kinase is an important enzyme involved in xylose metabolism, which is considered as essential biocatalyst for sustainable lignocellulosic-derived pentose utilization. Bacillus coagulans IPE22 is an ideal bacterium for refinery due to its strong ability to ferment xylose at high temperature. However, the B. coagulans xylose utilization mechanism remains unclear and the related promising enzymes need to be developed. In the present study, the gene coding for xylulose kinase from B. coagulans IPE22 (Bc-XK) was expressed in Escherichia coli BL21 (DE3). Bc-XK has a 1536 bp open reading frame, encoding a protein of 511 amino acids (56.15 kDa). Multiple sequence alignments were performed and a phylogenetic tree was built to evaluate differences among Bc-XK and other bacteria homologs. Bc-XK showed a broad adaptability to high temperature and the enzyme displayed its best performance at pH 8.0 and 60 °C. Bc-XK was activated by Mg , Mn , and Co . Meanwhile, the enzyme could keep activity at 60 °C for at least 180 min. K values of Bc-XK for xylulose and ATP were 1.29 mM and 0.76 mM, respectively. The high temperature stability of Bc-XK implied that it was an attractive candidate for industrial application.
木酮糖激酶是木糖代谢中的一种重要酶，被认为是可持续利用木质纤维素衍生戊糖的必需生物催化剂。凝结芽孢杆菌 IPE22 由于其在高温下发酵木糖的能力很强，是一种用于炼油厂的理想细菌。然而，凝结芽孢杆菌利用木糖的机制尚不清楚，需要开发相关的有前途的酶。在本研究中，来自凝结芽孢杆菌 IPE22 的木酮糖激酶基因（Bc-XK）在大肠杆菌 BL21（DE3）中表达。Bc-XK 具有 1536bp 的开放阅读框，编码 511 个氨基酸的蛋白质（56.15kDa）。进行了多序列比对，并构建了系统发育树，以评估 Bc-XK 与其他细菌同源物之间的差异。Bc-XK 对高温具有广泛的适应性，该酶在 pH8.0 和 60°C 下表现出最佳性能。Bc-XK 被 Mg 、 Mn 和 Co 激活。同时，该酶在 60°C 下至少 180min 保持活性。Bc-XK 对木酮糖和 ATP 的 K 值分别为 1.29mM 和 0.76mM。Bc-XK 的高温稳定性表明它是工业应用的有吸引力的候选者。
