Laboratoire de Cristallographie et RMN biologiques, UMR 8015-Cente National de la Recherche Scientifique, Paris, France.
PLoS One. 2012;7(12):e52424. doi: 10.1371/journal.pone.0052424. Epub 2012 Dec 20.
FimX is a large multidomain protein containing an EAL domain and involved in twitching motility in Pseudomonas aeruginosa. We present here two crystallographic structures of the EAL domain of FimX (residues 438-686): one of the apo form and the other of a complex with 5'-pGpG, the reaction product of the hydrolysis of c-di-GMP. In both crystal forms, the EAL domains form a dimer delimiting a large cavity encompassing the catalytic pockets. The ligand is trapped in this cavity by its sugar phosphate moiety. We confirmed by NMR that the guanine bases are not involved in the interaction in solution. We solved here the first structure of an EAL domain bound to the reaction product 5'-pGpG. Though isolated FimX EAL domain has a very low catalytic activity, which would not be significant compared to other catalytic EAL domains, the structure with the product of the reaction can provides some hints in the mechanism of hydrolysis of the c-di-GMP by EAL domains.
FimX 是一种包含 EAL 结构域的大型多功能蛋白，参与铜绿假单胞菌的扭动运动。我们在此呈现 FimX 的 EAL 结构域（残基 438-686）的两个晶体结构：一个是apo 形式，另一个是与 5'-pGpG 的复合物形式，5'-pGpG 是 c-di-GMP 水解的反应产物。在两种晶体形式中，EAL 结构域形成二聚体，限定了一个包含催化口袋的大腔。配体通过其糖磷酸部分被捕获在该腔中。通过 NMR 我们证实，在溶液中，嘌呤碱基不参与相互作用。我们在这里解决了第一个与反应产物 5'-pGpG 结合的 EAL 结构域的结构。尽管分离的 FimX EAL 结构域的催化活性非常低，与其他催化 EAL 结构域相比，这并不显著，但与反应产物的结构可以为 EAL 结构域水解 c-di-GMP 的机制提供一些启示。
