Crystal structure of human RhoA in a dominantly active form complexed with a GTP analogue
Crystal structure of human RhoA in a dominantly active form complexed with a GTP analogue
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DOI：
10.1074/jbc.273.16.9656
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发表时间：
1998-04-17
影响因子：
4.8
通讯作者：
Hakoshima, T
中科院分区：
文献类型：
--
作者：
Ihara, K;Muraguchi, S;Hakoshima, T
小鸟苷三磷酸酶(GTP)的主要活性形式RhoA，RhoA(V14)与不可水解的GTP类似物鸟苷5‘-3-O-(硫代)三磷酸(GTP Gamma S)络合的2.4埃分辨晶体结构，揭示了与最近报道的RhoA-GDP相似的倍数(魏，Y.，张，Y.，德里文达，美国，刘，X.，Minor，W.，Nakamoto，R.K.，Somlyo，A.P.，和Derewenda，Z.S.(1997)NAT)。结构。比奥尔。4,699-703)，但在Switch I和Switch II中显示出很大的构象差异。这些变化在Switch I的分子表面产生疏水斑块，这被认为参与了其效应器的结合。与H-RAS和其他与GTP或GTP类似物结合的GTP酶相比，显著的构象差异位于涉及开关I和II的区域以及开关I和开关II之间的部分反平行β-折叠。除了这些差异，RhoA还包含四个插入或缺失位点，带有一个额外的螺旋亚域，似乎是包括Rad在内的Rho家族成员的特征，但在细节上有几个变异。这些位置也显示出与H-RAS的位置不同的大位移。ADP-核糖化残基ASN(41)由类CS外酶堆积在Trp(58)的吲哚环上，与Glu(40)的主链形成氢键。GTP酶对S的鸟苷部分的识别含有水介导的氢键，这似乎在Rho家族中很常见。这些结构差异使我们可以深入了解特定的相互作用部位与效应器以及与调节剂，如鸟嘌呤核苷酸交换因子(Genf)和鸟嘌呤核苷酸解离抑制物(GDI)。
The 2.4-Angstrom resolution crystal structure of a dominantly active form of the small guanosine triphosphatase (GTPase) RhoA, RhoA(V14), complexed with the nonhydrolyzable GTP analogue, guanosine 5'-3-O-(thio)triphosphate (GTP gamma S), reveals a fold similar to RhoA-GDP, which has been recently reported (Wei, Y., Zhang, Y., Derewenda, U., Liu, X., Minor, W., Nakamoto, R. K., Somlyo, A. V., Somlyo, A. P., and Derewenda, Z. S. (1997) Nat. Struct. Biol. 4, 699-703), but shows large conformational differences localized in switch I and switch II. These changes produce hydrophobic patches on the molecular surface of switch I, which has been suggested to be involved in its effector binding. Compared with H-Ras and other GTPases bound to GTP or GTP analogues, the significant conformational differences are located in regions involving switches I and II and part of the antiparallel beta-sheet between switches I and II. Key residues that produce these conformational differences were identified. In addition to these differences, RhoA contains four insertion or deletion sites with an extra helical subdomain that seems to be characteristic of members of the Rho family, including Rad, but with several variations in details. These sites also display large displacements from those of H-Ras. The ADP-ribosylation residue, Asn(41), by CS-like exoenzymes stacks on the indole ring of Trp(58) With a hydrogen bond to the main chain of Glu(40). The recognition of the guanosine moiety of GTP gamma S by the GTPase contains water-mediated hydrogen bonds, which seem to be common in the Rho family. These structural differences provide an insight into specific interaction sites with the effecters, as well as with modulators such as guanine nucleotide exchange factor (GEF) and guanine nucleotide dissociation inhibitor (GDI).