Key Laboratory for Feed Biotechnology of the Ministry of Agriculture, Feed Research Institute, Chinese Academy of Agricultural Sciences, No. 12 Zhongguancun South Street, Beijing, 100081, People's Republic of China.
World J Microbiol Biotechnol. 2012 Feb;28(2):687-92. doi: 10.1007/s11274-011-0863-7. Epub 2011 Aug 21.
A new xylanase gene, xynBM4, was cloned from Streptomyces megasporus DSM 41476 and expressed in Pichia pastoris. The full-length gene consists of 1,443 bp and encodes 480 amino acids including a putative 49-residue signal peptide. The deduced amino acid sequence of xynBM4 shows the highest identity of 66.3% to the xylanase Xys1L from Streptomyces halstedii JM8. The purified recombinant XYNBM4 had a high specific activity of 350.7 U mg(-1) towards soluble wheat arabinoxylan, exhibited optimal activity at pH 6.0 and 57°C, showed broad pH adaptability (>75% of the maximum activity at pH 2.5-9.0), was resistant to neutral proteases and most chemicals, and produced simple products. The hydrolysis products of birchwood xylan and corncob xylan were predominantly xylobiose (76.9 and 90.8%, respectively) and no xylose. These characteristics suggest that XYNBM4 has potential in various applications, especially in the food industry.
从链霉菌 megasporus DSM 41476 中克隆了一个新的木聚糖酶基因 xynBM4，并在毕赤酵母中表达。全长基因由 1443bp 组成，编码 480 个氨基酸，包括一个假定的 49 个残基的信号肽。xynBM4 的推导氨基酸序列与来自链霉菌 halstedii JM8 的木聚糖酶 Xys1L 的同源性最高，为 66.3%。纯化的重组 XYNBM4 对可溶性小麦阿拉伯木聚糖具有很高的比活性（350.7Umg-1），在 pH6.0 和 57°C 下表现出最佳活性，在 pH2.5-9.0 之间具有广泛的 pH 适应性（>75%的最大活性），对中性蛋白酶和大多数化学物质具有抗性，并且产生简单的产物。桦木木聚糖和玉米芯木聚糖的水解产物主要为木二糖（分别为 76.9%和 90.8%），没有木糖。这些特性表明 XYNBM4 在各种应用中具有潜力，特别是在食品工业中。
