Reymond Philippe, Coquard Aline, Chenon Mélanie, Zeghouf Mahel, El Marjou Ahmed, Thompson Andrew, Ménétrey Julie
Laboratoire d'Enzymologie et Biochimie Structurales, Centre de Recherche de Gif, CNRS, 91198 Gif-sur-Yvette, France.
Acta Crystallogr Sect F Struct Biol Cryst Commun. 2012 Jun 1;68(Pt 6):626-31. doi: 10.1107/S1744309112013541. Epub 2012 May 22.
RGK proteins are atypical small GTP-binding proteins that are involved in the regulation of voltage-dependent calcium channels and actin cytoskeleton remodelling. The structure of the Rem2 G domain bound to GDP is reported here in a monoclinic crystal form at 2.66 Å resolution. It is very similar to the structure determined previously from an orthorhombic crystal form. However, differences in the crystal-packing environment revealed that the switch I and switch II regions are flexible and not ordered as previously reported. Comparison of the available RGK protein structures along with those of other small GTP-binding proteins highlights two structural features characteristic of this atypical family and suggests that the conserved tryptophan residue in the DXWEX motif may be a structural determinant of the nucleotide-binding affinity.
RGK蛋白是一类非典型的小GTP结合蛋白，参与电压依赖性钙通道的调节和肌动蛋白细胞骨架重塑。本文报道了与GDP结合的Rem2 G结构域以单斜晶形式在2.66 Å分辨率下的结构。它与先前从正交晶形式确定的结构非常相似。然而，晶体堆积环境的差异表明，开关I和开关II区域是灵活的，不像先前报道的那样有序。将现有的RGK蛋白结构与其他小GTP结合蛋白的结构进行比较，突出了这个非典型家族的两个结构特征，并表明DXWEX基序中保守的色氨酸残基可能是核苷酸结合亲和力的结构决定因素。
