Whitehead T R
National Center for Agricultural Utilization Research, United States Department of Agriculture, Peoria, Illinois 61604.
Curr Microbiol. 1993 Jul;27(1):27-33. doi: 10.1007/BF01576830.
The DNA sequence for the xylanase gene from Prevotella (Bacteroides) ruminicola 23 was determined. The xylanase gene encoded for a protein with a molecular weight of 65,740. An apparent leader sequence of 22 amino acids was observed. The promoter region for expression of the xylanase gene in Bacteroides species was identified with a promoterless chloramphenicol acetyltransferase gene. A region of high amino acid homology was found with the proposed catalytic domain of endoglucanases from several organisms, including Butyrivibrio fibrisolvens, Ruminococcus flavefaciens, and Clostridium thermocellum. The cloned xylanase was found to exhibit endoglucanase activity against carboxymethyl cellulose. Analysis of the codon usage for the xylanase gene found a bias towards G and C in the third position in 16 of 18 amino acids with degenerate codons.
测定了普氏栖瘤胃菌（拟杆菌属）23的木聚糖酶基因的DNA序列。该木聚糖酶基因编码一种分子量为65740的蛋白质。观察到一段明显的由22个氨基酸组成的前导序列。利用无启动子氯霉素乙酰转移酶基因鉴定了拟杆菌属物种中木聚糖酶基因表达的启动子区域。发现该基因与几种生物（包括溶纤维丁酸弧菌、黄化瘤胃球菌和热纤梭菌）的内切葡聚糖酶的推测催化结构域具有高度氨基酸同源性。发现克隆的木聚糖酶对羧甲基纤维素具有内切葡聚糖酶活性。对木聚糖酶基因密码子使用情况的分析发现，在18个具有简并密码子的氨基酸中，有16个在第三位偏向于G和C。
