视紫红质-转导蛋白偶联：Gα 羧基末端在核苷酸交换催化中的作用。
Rhodopsin-transducin coupling: role of the Galpha C-terminus in nucleotide exchange catalysis.
作者信息
Herrmann Rolf, Heck Martin, Henklein Peter, Kleuss Christiane, Wray Victor, Hofmann Klaus Peter, Ernst Oliver P
机构信息
Institut für medizinische Physik und Biophysik (CCM), Charité-Universitätsmedizin Berlin, Schumannstr. 20/21, 10098 Berlin, Germany.
出版信息
Vision Res. 2006 Dec;46(27):4582-93. doi: 10.1016/j.visres.2006.07.027. Epub 2006 Sep 29.
In the early steps of visual signal transduction, light-activated rhodopsin (R*) catalyzes GDP/GTP exchange in the heterotrimeric G protein (Galphabetagamma) transducin. We recently reported that the catalytic interaction involves two sequential steps. An initial docking between R* and Gbetagamma leads to conformational changes which make the C-terminus of Galpha (CTalpha) available for binding to R*. Binding of CTalpha by R* then triggers GDP/GTP exchange in the Galpha subunit. To further study this two-step mechanism, we investigated different single amino acid substitutions within CTalpha and discuss the effects of high affinity mutations on nucleotide exchange catalysis.
在视觉信号转导的早期步骤中，光激活的视紫红质（R*）催化异源三聚体G蛋白（Gαβγ）转导素中的GDP/GTP交换。我们最近报道，催化相互作用涉及两个连续步骤。R与Gβγ之间的初始对接导致构象变化，使Gα的C末端（CTα）可用于与R结合。R*对CTα的结合随后触发Gα亚基中的GDP/GTP交换。为了进一步研究这种两步机制，我们研究了CTα内不同的单氨基酸取代，并讨论了高亲和力突变对核苷酸交换催化的影响。
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