Section 51
Chapter 50,220

Rhodopsin-transducin coupling: role of the Galpha C-terminus in nucleotide exchange catalysis

Herrmann, R.; Heck, M.; Henklein, P.; Kleuss, C.; Wray, V.; Hofmann, K.Peter.; Ernst, O.P.

Vision Research 46(27): 4582-4593


ISSN/ISBN: 0042-6989
PMID: 17011013
DOI: 10.1016/j.visres.2006.07.027
Accession: 050219241

Download citation:  

In the early steps of visual signal transduction, light-activated rhodopsin (R*) catalyzes GDP/GTP exchange in the heterotrimeric G protein (G alpha beta gamma) transducin. We recently reported that the catalytic interaction involves two sequential steps. An initial docking between R* and G beta gamma leads to conformational changes which make the C-terminus of G alpha (CT alpha) available for binding to R*. Binding of CT alpha by R* then triggers GDP/GTP exchange in the G alpha subunit. To further study this two-step mechanism, we investigated different single amino acid substitutions within CT alpha and discuss the effects of high affinity mutations on nucleotide exchange catalysis.

PDF emailed within 0-6 h: $19.90