Fusobacterium nucleatum, the first Gram-negative bacterium demonstrated to produce polyglutamate
Fusobacterium nucleatum, the first Gram-negative bacterium demonstrated to produce polyglutamate
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DOI：
10.1139/w09-003
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发表时间：
2009-05-01
影响因子：
2.8
通讯作者：
Fouet, Agnes
中科院分区：
文献类型：
--
作者：
Candela, Thomas;Moya, Marie;Fouet, Agnes
在许多革兰氏阳性微生物中已经描述了聚-γ-谷氨酸盐。当锚定到表面时，它是一个胶囊，因此是一个毒力因子。基于序列相似性，很少有革兰氏阴性生物被认为能合成聚-γ-谷氨酸。第一次，一种革兰氏阴性细菌，具核梭杆菌，显示出产生和分泌聚-γ-谷氨酸。来自革兰氏阴性生物体的推定的多聚-γ-谷氨酸合成基因已经通过计算机分析与它们的革兰氏阳性同源物进行了比较，即，基因序列和系统发育分析。我们的屏幕突出显示了三个而不是四个基因的簇。前两个基因的产物显示与它们的革兰氏阳性等同物的相似性，但是来自革兰氏阴性生物体的序列可以与革兰氏阳性生物体的序列区分开。有趣的是，第三个基因的预测产物的序列在革兰氏阴性细菌中是保守的，但与革兰氏阳性操纵子的第三个或第四个基因的序列没有相似性。有人建议，像革兰氏阳性菌，聚-γ-谷氨酸具有的作用，在致病菌的毒力和其他革兰氏阴性菌的生存之一。
Poly-gamma-glutamate has been described in many Gram-positive organisms. When anchored to the surface, it is a capsule and as such a virulence factor. Based on sequence similarities, few Gram-negative organisms have been suggested to synthesize poly-gamma-glutamate. For the first time, a Gram-negative bacterium, Fusobacterium nucleatum, is shown to produce and secrete poly-gamma-glutamate. Putative poly-gamma-glutamate-synthesizing genes from Gram-negative organisms have been compared with their Gram-positive homologs by in silico analysis, i.e., gene sequence and phylogenetic analysis. Clusters of three instead of four genes were highlighted by our screen. The products of the first two genes display similarity with their Gram-positive equivalents, yet the sequences from the Gram-negative organisms can be distinguished from those of the Gram-positives. Interestingly, the sequence of the predicted product of the third gene is conserved among Gram-negative bacteria but displays no similarity to that of either the third or fourth gene of the Gram-positive operons. It is suggested that, like for Gram-positive bacteria, poly-gamma-glutamate has a role in virulence for pathogens and one in survival for other Gram-negative bacteria.