Dcsbis (PA2771) from Pseudomonas aeruginosa is a highly active diguanylate cyclase with unique activity regulation.
Dcsbis (PA2771) from Pseudomonas aeruginosa is a highly active diguanylate cyclase with unique activity regulation.
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来自铜绿假单胞菌的 Dcsbis (PA2771) 是一种具有独特活性调节的高活性二鸟苷酸环化酶
DOI：
10.1038/srep29499
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发表时间：
2016-07-08
影响因子：
4.6
通讯作者：
Gu L
中科院分区：
文献类型：
--
作者：
Chen Y;Liu S;Liu C;Huang Y;Chi K;Su T;Zhu D;Peng J;Xia Z;He J;Xu S;Hu W;Gu L
C-di-GMP（3 '，5' -环二鸟苷酸）是细菌中重要的第二信使，其影响毒力、运动性、生物膜形成和细胞分裂。细胞中c-di-GMP的水平由二胍基环化酶（DGC）和磷酸二酯酶（PDE）控制。在这里，我们报告的生化功能和晶体结构的潜在的双鸟苷酸酶Dcsbis（PA 2771，一个双鸟苷酸环化酶与自我封闭的I-网站）从铜绿假单胞菌PAO 1。全长Dcsbis蛋白含有N-末端GAF结构域和C-末端GGDEF结构域。我们发现，Dcsbis紧密协调细胞运动，而不显着影响生物膜的形成，是一种双鸟苷酸环化酶的催化活性远高于许多其他DGCs。出乎意料的是，我们发现从GAF结构域延伸的肽环（保护环）占据了保守的抑制位点，从而大大减轻了产物抑制作用。在GAF结构域中观察到大的疏水口袋，因此表明未知的上游信号传导分子可能与GAF结构域结合，将保护环从I位点移动，从而关闭酶活性。
C-di-GMP (3’,5’ -Cyclic diguanylic acid) is an important second messenger in bacteria that influences virulence, motility, biofilm formation, and cell division. The level of c-di-GMP in cells is controlled by diguanyl cyclases (DGCs) and phosphodiesterases (PDEs). Here, we report the biochemical functions and crystal structure of the potential diguanylase Dcsbis (PA2771, a diguanylate cyclase with a self-blocked I-site) from Pseudomonas aeruginosa PAO1. The full-length Dcsbis protein contains an N-terminal GAF domain and a C-terminal GGDEF domain. We showed that Dcsbis tightly coordinates cell motility without markedly affecting biofilm formation and is a diguanylate cyclase with a catalytic activity much higher than those of many other DGCs. Unexpectedly, we found that a peptide loop (protecting loop) extending from the GAF domain occupies the conserved inhibition site, thereby largely relieving the product-inhibition effect. A large hydrophobic pocket was observed in the GAF domain, thus suggesting that an unknown upstream signaling molecule may bind to the GAF domain, moving the protecting loop from the I-site and thereby turning off the enzymatic activity.