MRC Laboratory of Molecular Biology, Structural Studies Division, Francis Crick Avenue, Cambridge CB2 0QH, United Kingdom.
MRC Laboratory of Molecular Biology, Structural Studies Division, Francis Crick Avenue, Cambridge CB2 0QH, United Kingdom.
FEBS Lett. 2014 Mar 3;588(5):776-82. doi: 10.1016/j.febslet.2014.01.029. Epub 2014 Jan 28.
Polymerising proteins of the actin family are nearly ubiquitous. Crenactins, restricted to Crenarchaea, are more closely related to actin than bacterial MreB. Crenactins occur in gene clusters hinting at an unknown, but conserved function. We solved the crystal structure of crenactin at 3.2 Å resolution. The protein crystallises as a continuous right-handed helix with 8 subunits per complete turn, spanning 419 Å. The structure of crenactin shows several loops that are longer than in actin, but overall, crenactin is closely related to eukaryotic actin, with an RMSD of 1.6 Å. Crenactin filaments imaged by electron microscopy showed polymers with very similar helical parameters.
肌动蛋白家族的聚合蛋白几乎无处不在。局限于泉古菌的泉古菌素与肌动蛋白的关系比细菌的 MreB 更为密切。泉古菌素存在于基因簇中，暗示着一种未知但保守的功能。我们以 3.2Å 的分辨率解决了泉古菌素的晶体结构。该蛋白以连续的右手螺旋形式结晶，每完整一转有 8 个亚基，跨度为 419Å。泉古菌素的结构显示出几个比肌动蛋白更长的环，但总的来说，泉古菌素与真核肌动蛋白密切相关，RMSD 为 1.6Å。通过电子显微镜观察到的泉古菌素纤维显示出具有非常相似螺旋参数的聚合物。
