Brahamsha B, Han C Y, Crawford I P, Greenberg E P
Department of Molecular Genetics and Cell Biology, University of Chicago, Illinois 60637.
J Bacteriol. 1991 Jan;173(2):541-8. doi: 10.1128/jb.173.2.541-548.1991.
A Spirochaeta aurantia DNA fragment containing the trpE gene and flanking chromosomal DNA was cloned, and the sequence of the trpE structural gene plus 870 bp upstream and 1,257 bp downstream of trpE was determined. The S. aurantia trpE gene codes for a polypeptide of 482 amino acid residues with a predicted molecular weight of 53,629 that showed sequence similarity to TrpE proteins from other organisms. The S. aurantia TrpE polypeptide is not more closely related to the other published spirochete TrpE sequence (that of Leptospira biflexa) than to TrpE polypeptides of other bacteria. Two additional complete open reading frames and one partial open reading frame were identified in the sequenced DNA. One of the complete open reading frames and the partial open reading frame are upstream of trpE and are encoded on the DNA strand opposite that containing trpE. The other open reading frame is downstream of trpE and on the same DNA strand as trpE. On the basis of the results of a protein sequence data base search, it appears that trpE is the only tryptophan biosynthesis gene in the sequenced DNA. This is in contrast to L. biflexa, in which trpE is separated from trpG by only 64 bp.
一个包含色氨酸操纵子E基因（trpE）及侧翼染色体DNA的橙色螺旋体（Spirochaeta aurantia）DNA片段被克隆出来，并且测定了trpE结构基因加上trpE上游870 bp和下游1257 bp的序列。橙色螺旋体的trpE基因编码一个由482个氨基酸残基组成的多肽，预测分子量为53,629，该多肽与其他生物体的TrpE蛋白显示出序列相似性。橙色螺旋体的TrpE多肽与其他已发表的螺旋体TrpE序列（双曲钩端螺旋体的序列）相比，与其他细菌的TrpE多肽并没有更密切的关系。在测序的DNA中鉴定出另外两个完整的开放阅读框和一个部分开放阅读框。其中一个完整的开放阅读框和部分开放阅读框在trpE的上游，并且在与包含trpE的DNA链相反的链上编码。另一个开放阅读框在trpE的下游，并且与trpE在同一条DNA链上。根据蛋白质序列数据库搜索的结果，似乎trpE是测序DNA中唯一的色氨酸生物合成基因。这与双曲钩端螺旋体不同，在双曲钩端螺旋体中trpE与trpG仅相隔64 bp。
