鸟嘌呤核苷酸交换因子人Mss4的结构及其Rab相互作用表面的鉴定。

Structure of guanine-nucleotide-exchange factor human Mss4 and identification of its Rab-interacting surface.

作者信息

Yu H, Schreiber S L

机构信息

Howard Hughes Medical Institute, Department of Chemistry, Harvard University, Cambridge, Massachusetts 02138, USA.

出版信息

Nature. 1995 Aug 31;376(6543):788-91. doi: 10.1038/376788a0.

DOI:10.1038/376788a0

PMID:7651540

Abstract

Guanine-nucleotide-exchange factors (GEFs) promote the exchange of GDP for GTP in Ras GTPases, and thereby positively regulate their functions. Members of the Sec4/Ypt1/Rab branch of the Ras superfamily are essential for vesicular transport. A GEF for a subset of Rab proteins, termed mammalian suppressor of Sec4 (Mss4), has been identified. Here we use multidimensional NMR to determine the structure of human Mss4 (hMss4), which is the first tertiary structure established for a protein with GEF activity. Mss4 contains a central beta-sheet sandwiched between two small sheets. It also binds a Zn2+ ion through Cys 23, Cys 26, Cys 94 and Cys 97. The Rab-binding surface of hMss4 has subsequently been delineated using chemical-shift perturbation experiments and site-directed mutagenesis. The active site of hMss4 involves the Zn(2+)-binding region and a neighbouring loop.

摘要

鸟嘌呤核苷酸交换因子（GEFs）促进Ras GTP酶中GDP与GTP的交换，从而正向调节其功能。Ras超家族的Sec4/Ypt1/Rab分支成员对囊泡运输至关重要。已鉴定出一种Rab蛋白亚群的GEF，称为Sec4的哺乳动物抑制因子（Mss4）。在这里，我们使用多维核磁共振来确定人Mss4（hMss4）的结构，这是为具有GEF活性的蛋白质建立的第一个三级结构。Mss4包含一个夹在两个小薄片之间的中央β折叠。它还通过Cys 23、Cys 26、Cys 94和Cys 97结合一个Zn2+离子。随后，利用化学位移扰动实验和定点诱变确定了hMss4的Rab结合表面。hMss4的活性位点涉及Zn(2+)结合区域和相邻环。