Structural Determinants for Interaction with Three Different Effectors on the G Protein β Subunit*-猫眼课题宝

与 G 蛋白 β 亚基上三种不同效应子相互作用的结构决定因素*

DOI：

10.1074/jbc.272.4.2056

发表时间：

1997

期刊：

The Journal of Biological Chemistry

影响因子：

通讯作者：

中科院分区：

文献类型：

作者：

K. Yan;N. Gautam

In the yeast two-hybrid system, a 100-residue fragment (β1A) from the N terminus of the β1 subunit interacts with domains specific to adenylyl cyclase 2 (AC2), the muscarinic atrial potassium channel (GIRK1), and phospholipase C-β2 (PLC-β2). Based on the crystal structure of the G protein, β1A is composed of an N-terminal α helix, a loop, and five β strands in which the C-terminal four β strands form a β sheet, the first of seven sheets that make up the propeller structure of the β subunit. A mutant of β1A (L4P, L7P, and L14P), in which the α helix was potentially destroyed, interacted poorly with the G protein γ subunit but effectively with domains of AC2, GIRK1, and PLC-β2. In contrast, another mutant of β1A (S72A, D76A, and W82A), in which a network of hydrogen bonds was disrupted, interacted poorly with GIRK1 and PLC-β2 domains, but effectively with the γ subunit and the AC2 domain. These results suggest that the proper folding of the first five β strands in the G protein β subunit is a requirement for appropriately positioning residues that interact with GIRK1 and PLC-β2. Furthermore, since mutations that potentially disrupted the folding of these β strands did not affect interaction with AC2, the structural determinants on the G protein β subunit for interaction with various effectors may be different.