Improving special hydrolysis characterization into Talaromyces thermophilus F1208 xylanase by engineering of N-terminal extension and site-directed mutagenesis in C-terminal
Improving special hydrolysis characterization into Talaromyces thermophilus F1208 xylanase by engineering of N-terminal extension and site-directed mutagenesis in C-terminal
复制标题
通过 N 端延伸工程和 C 端定点诱变改善嗜热踝节菌 F1208 木聚糖酶的特殊水解特性
DOI：
10.1016/j.ijbiomac.2016.12.050
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发表时间：
2017-03-01
影响因子：
8.2
通讯作者：
Li, Xiuting
中科院分区：
文献类型：
--
作者：
Li, Qin;Sun, Baoguo;Li, Xiuting
本研究旨在了解木聚糖酶在低聚木糖生产中的水解特性，并通过蛋白质工程对其进行改良。本研究以嗜热篮状菌F1208木聚糖酶（T-Xyn）为出发菌株，将其N端的Phe 1-Pro 16替换为Ala 1-Gln 8，C端的Phe 193（185）替换为Ser，构建了一种杂合酶（T-XynFM）。该酶在55 ℃和pH6.5时表现出最佳活性。T-XynFM对山毛榉木聚糖、桦木木聚糖和燕麦木聚糖的Km值分别为10.31、10.03和8.90 mg/mL（-1）。该酶具有独特的水解特性，对木三糖（X3）、木四糖（X4）和木五糖几乎不产生木糖。X3的水解产物中X4的含量超过60%，表明T-XynFM具有强大的转糖基化特性。(C)2016爱思唯尔B. V.保留所有权利。
The purpose of this study was to gain insights into the hydrolysis characteristics of xylanase in producing xylo-oligosaccharides and to improve these by protein engineering. In this study, a hybrid enzyme (T-XynFM) was created from Talaromyces thermophilus F1208 xylanase (T-Xyn) by replacement of the N-terminal extension Phe1-Pro16 with Ala1-Gln8 and substitution of amino acid Phe193 (185) with Ser in the C-terminal. The enzyme showed optimum activity at 55 degrees C and pH 6.5. Its residual activity was more than 55% after treatment at 50 degrees C, pH 6.5 for 12 h Km values of T-XynFM for beechwood xylan, birchwood xylan, and oat-spelt xylan were 10.31, 10.03, and 8.90 mg mL(-1), respectively. The enzyme displayed special hydrolysis characteristics: almost no xylose was produced on using xylotriose (X3), xylotetraose (X4), and xylopentaose as substrates. Moreover, over 60% X4 existed in hydrolyzed products of X3, indicating that T-XynFM possesses formidable transglycosylation properties. (C) 2016 Elsevier B.V. All rights reserved.