Okada Masahiro
Department of Chemistry, Graduate School of Science, Tohoku University, Aooba-ku, Sendai, Japan.
Biosci Biotechnol Biochem. 2011;75(8):1413-7. doi: 10.1271/bbb.110087. Epub 2011 Aug 7.
Bacillus subtilis and related bacilli produce a post-translationally modified oligopeptide, ComX pheromone, that stimulates natural genetic competence controlled by quorum sensing. The ComX pheromones are formed by geranylation or farnesylation on a tryptophan residue at the 3 position of its indole ring. This results in the formation of a tricyclic structure including, a newly formed five-membered ring, similar to proline. Isoprenylation of ComX to form ComX pheromones is essential for pheromonal activity, and is functionally more crucial than its amino acid sequence. The ComX pheromone is the first example of isoprenoidal modifiations of tryptophan residues in living organisms and post-translational isoprenylation of any amino acid in prokaryotes. Because the presence of geranylated compounds is unusual in primary and secondary metabolites outside the plant kingdom, post-translational geranylation in bacilli is unprecedented in nature.
枯草芽孢杆菌及相关芽孢杆菌会产生一种翻译后修饰的寡肽——ComX信息素，它能刺激由群体感应控制的自然遗传转化能力。ComX信息素是通过在其吲哚环3位的色氨酸残基上进行香叶基化或法尼基化形成的。这导致形成一种三环结构，包括一个新形成的类似于脯氨酸的五元环。ComX的异戊烯基化形成ComX信息素对于信息素活性至关重要，并且在功能上比其氨基酸序列更关键。ComX信息素是生物体中色氨酸残基的类异戊二烯修饰以及原核生物中任何氨基酸的翻译后异戊烯基化的首个实例。由于在植物界以外的初级和次级代谢产物中，香叶基化化合物的存在并不常见，因此芽孢杆菌中的翻译后香叶基化在自然界中是前所未有的。
