Spickofsky N, Robichon A, Danho W, Fry D, Greeley D, Graves B, Madison V, Margolskee R F
Roche Institute of Molecular Biology, Nutley, NJ 07110, USA.
Nat Struct Biol. 1994 Nov;1(11):771-81. doi: 10.1038/nsb1194-771.
In vertebrate rod cells, the activated alpha-subunit of rod transducin interacts with the gamma (regulatory) subunits of phosphodiesterase to disinhibit the catalytic subunits. A 22-amino acid long region of rod transducin involved in phosphodiesterase activation has recently been identified. We have used peptides from this region of rod transducin and from several other G protein alpha-subunits to study the nature and specificity of the G protein alpha-effector interaction. Although peptides derived from rod transducin, cone transducin and gustducin are similar, only the rod peptide is capable of activating rod phosphodiesterase. Using substituted peptides we have identified five residues on one exposed face of rod transducin as important to phosphodiesterase activation. These results disagree with previous models which propose that loop regions of rod transducin interact with phosphodiesterase gamma.
在脊椎动物视杆细胞中，被激活的视杆转导蛋白α亚基与磷酸二酯酶的γ（调节）亚基相互作用，从而解除对催化亚基的抑制。最近已鉴定出视杆转导蛋白中一段参与磷酸二酯酶激活的22个氨基酸长的区域。我们使用了来自视杆转导蛋白这一区域以及其他几种G蛋白α亚基的肽段，来研究G蛋白α亚基与效应器相互作用的性质和特异性。尽管源自视杆转导蛋白、视锥转导蛋白和味觉转导蛋白的肽段相似，但只有视杆肽段能够激活视杆磷酸二酯酶。通过使用取代肽段，我们已确定视杆转导蛋白一个暴露面上的五个残基对磷酸二酯酶激活很重要。这些结果与之前提出视杆转导蛋白的环区与磷酸二酯酶γ相互作用的模型不一致。
