Umemoto Hirohito, Inami Mayuko, Yatsunami Rie, Fukui Toshiaki, Kumasaka Takashi, Tanaka Nobuo, Nakamura Satoshi
Department of Bioengineering, Graduate School of Bioscience and Biotechnology, Tokyo Institute of Technology, 4259 Nagatsuta, Midori-ku, Yokohama 226-8501, Japan.
Nucleic Acids Symp Ser (Oxf). 2007(51):461-2. doi: 10.1093/nass/nrm231.
Xylanase J (XynJ) from alkaliphilic Bacillussp. strain 41M-1 is an alkaline xylanase. Structure comparison indicated that there were several specific salt bridges in the catalytic cleft of XynJ compared with neutral xylanases. Mutant enzymes were prepared by substituting several amino acids comprising the salt bridges. Some mutants exhibited acidophilic shift in optimum pH, whereas another showed alkaliphilic shift. These results suggested that the characteristic salt bridges could contribute to the alkaliphily of XynJ.
来自嗜碱芽孢杆菌菌株41M-1的木聚糖酶J（XynJ）是一种碱性木聚糖酶。结构比较表明，与中性木聚糖酶相比，XynJ的催化裂隙中存在几个特定的盐桥。通过替换构成盐桥的几个氨基酸制备了突变酶。一些突变体在最适pH值上表现出嗜酸位移，而另一些则表现出嗜碱位移。这些结果表明，这些特征性盐桥可能有助于XynJ的嗜碱性。
