The structure of the Guanine Nucleotide Exchange Factor Rlf in complex with the small G-protein Ral identifies conformational intermediates of the exchange reaction and the basis for the selectivity

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• 作者：Milica Popovic^a ; Arie Schouten^b ; Marije Rensen-de Leeuw^a ; Holger Rehmann^a ; ^{h.rehmann@umcutrecht.nl" class="auth_mail" title="E-mail the corresponding author}
• 关键词：Ras-family of G-proteins ; Induced fit ; CDC25-homology domain ; Guanine nucleotide exchange reaction
• 刊名：Journal of Structural Biology
• 出版年：2016
• 出版时间：February 2016
• 年：2016
• 卷：193
• 期：2
• 页码：106-114
• 全文大小：2224 K

文摘

CDC25 homology domain (CDC25-HD) containing Guanine Nucleotide Exchange Factors (GEFs) initiate signalling by small G-proteins of the Ras-family. Each GEF acts on a small subset of the G-proteins only, thus providing signalling selectivity. Rlf is a GEF with selectivity for the G-proteins RalA and RalB. Here the crystal structure of Rlf in complex with Ral is determined. The Rlf·Ral complex crystallised into two different crystal forms, which represent different steps of the exchange reaction. Thereby general insight in the CDC25-HD catalysed nucleotide exchange is obtained. In addition, the basis for the selectivity of the interaction is investigated. The exchange activity is monitored by the use of recombinant proteins. Selectivity determinants in the binding interface are identified and confirmed by a mutational study.