H-ras p21突变体的三维结构:它们无法作为信号交换机分子发挥作用的分子基础
U Krengel1, I Schlichting, A Scherer
1Max-Planck-Institut für medizinische Forschung Abteilung Biophysik, Heidelberg, Federal Republic of Germany.
Cell
|August 10, 1990
概括
对H-ras瘤基因突变的结构分析揭示了特定突变如何影响GTP结合和水解. 这些发现对于理解瘤性转变和开发向疗法至关重要.
科学领域:
- 生物化学 生物化学
- 分子生物学分子生物学
- 结构生物学 结构生物学
背景情况:
- H-ras瘤基因产物p21是细胞信号通路的关键调节者.
- 在各种人类癌症中经常发现H-ras的突变,导致不受控制的细胞生长.
- 了解H-ras突变的结构基础对于开发向癌症疗法至关重要.
研究的目的:
- 为了确定五个H-ras p21突变的X射线结构.
- 阐明这些突变影响GTP结合和水解的结构机制.
- 研究突变对与GTP和GTPase激活蛋白 (GAP) 的相互作用的影响.
主要方法:
- 采用X射线晶体学,确定了五种H-ras p21突变的关氨酸核酸结合域的结构.
- 晶体结构的分辨率在2.0至2.6 Å之间.
- 在野生类型和突变p21蛋白之间进行了比较结构分析.
主要成果:
- 在Gly-12 (Gly-12----Arg,Gly-12----Val) 的突变引入更大的侧链,干扰GTP结合和/或水解.
- 在Gln-61 (Gln-61----His, Gln-61----Leu) 的突变阻止了采用GTP水解所需的形状.
- 在效应器区域的Asp-38----Glu (D38E) 突变保留了结合GAP的能力,表明信号功能被保留了.
结论:
- 细胞和突变p21蛋白之间的结构差异是微妙的,主要影响循环L4和玛酸盐附近.
- 在Gly-12和Gln-61的突变直接损害了H-ras p21的内在GTPase活性.
- D38E突变突出了不同区域在H-ras p21功能和GAP相互作用中的不同角色.
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