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对ARF1-ARFGAP复合物的结构和功能分析揭示了coatomer在GTP水解中的作用
1Cellular Biochemistry and Biophysics Program, Memorial Sloan-Kettering Cancer Center, New York, New York 10021, USA. jonathan@ximpact4.ski.mskcc.org
Cell
|April 2, 1999
概括
在ARF1 GTPase激活蛋白 (ARFGAP) 和coatomer复合体结构揭示了ARFGAP如何促进GTP水解. 这个三方复合体控制COPI囊泡层的拆卸.
科学领域:
- 分子生物学分子生物学
- 结构生物学是结构生物学.
- 生物化学 生物化学
背景情况:
- ADP-ribosylation factor 1 (ARF1) 是一个小的GTPase,对囊泡运输至关重要.
- 通过促进GTP水解,ARF GTP酶激活蛋白 (ARFGAPs) 调节ARF1的活动.
- 覆盖COPI的囊泡参与了戈尔吉装置内的逆行运输.
研究的目的:
- 阐明ARFGAP介导的ARF1.1监管的结构基础.
- 了解在GTPase反应中的coatomer的作用.
- 为了描述控制COPI囊泡层拆卸的三方复合体.
主要方法:
- 在1.95A分辨率的X射线晶体学以确定复杂的结构.
- 生物化学测定以评估GTP水解速率.
主要成果:
- 晶体结构显示ARFGAP与ARF1的交换机2和螺旋alpha3结合,在没有直接参与活性位点的情况下引导残留物进行催化.
- 在综合体内,ARF1的效应器结合区域仍然可访问.
- 生物化学实验表明,coatomer以ARFGAP-依赖的方式加速GTP水解的1000倍.
结论:
- 一个涉及ARF1,ARFGAP和coatomer的三方复合体对于调节GTP水解至关重要.
- 这个复合体触发了COPI囊泡层的分解.
- 这些发现提供了关于囊泡运输调节的分子机制的见解.
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