[HTML][HTML] Crystal structure at 2.4 Å resolution of the complex of transducin βγ and its regulator, phosducin

R Gaudet, A Bohm, PB Sigler - Cell, 1996 - cell.com
R Gaudet, A Bohm, PB Sigler
Cell, 1996cell.com
The crystal structure of transducin's βγ subunits complexed with phosducin, which regulates
G t βγ activity, has been solved to 2.4 Å resolution. Phosducin has two domains that wrap
around G t βγ to form an extensive interface. The N-terminal domain binds loops on the" top"
G t β surface, overlapping the G t α binding surface, explaining how phosducin blocks G t
βγ's interaction with G t α. The C-terminal domain shows structural homology to thioredoxin
and binds the outer strands of G t β's seventh and first blades in a manner likely to disrupt G t …
Abstract
The crystal structure of transducin's βγ subunits complexed with phosducin, which regulates Gtβγ activity, has been solved to 2.4 Å resolution. Phosducin has two domains that wrap around Gtβγ to form an extensive interface. The N-terminal domain binds loops on the "top" Gtβ surface, overlapping the Gtα binding surface, explaining how phosducin blocks Gtβγ's interaction with Gtα. The C-terminal domain shows structural homology to thioredoxin and binds the outer strands of Gtβ's seventh and first blades in a manner likely to disrupt Gtβγ's normal orientation relative to the membrane and receptor. Phosducin's Ser-73, which when phosphorylated inhibits phosducin's function, points away from Gtβγ, toward a large flexible loop. Thus phosphorylation is not likely to affect the interface directly, but rather indirectly through an induced conformational change.
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