Determination of the depth of penetration of the alpha subunit of retinal G protein in membranes: a spectroscopic study.
This paper reports the fluorescence quenching of the alpha subunit of retinal rod outer segment G protein (Gtalpha) by vesicles of brominated phospholipids. Two different brominated phospholipids with the bromine quencher groups attached at the 6-7 and 9-10 positions in one of the fatty acyl chains have been used to estimate the depth of penetration of the Gtalpha protein in the lipid vesicles using steady-state fluorescence quenching techniques. Our studies provide evidence of the interaction between Gtalpha protein, in its active conformation, with the lipid vesicles mimicking natural membranes. This study demonstrates that in vitro the distance between fluorescent tryptophan site of Gtalpha and the membrane surface is approximately 6.5 A.
Grenier
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S
GREIB, Département de Chimie-Biologie, Université du Québec à Trois-Rivières, Trois-Rivières, Québec, Canada.
Desmeules
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P
Dutta
A K
AK
Yamazaki
A
A
Salesse
C
C
D000818:Animals; D002352:Carrier Proteins / Q000378:metabolism; D005136:Eye Proteins / Q000378:metabolism*; D005454:Fluorescence Polarization; D019204:GTP-Binding Proteins / Q000737:chemistry / Q000378:metabolism*; D020962:Heterotrimeric GTP-Binding Proteins; D007473:Ion Channels; D008081:Liposomes / Q000378:metabolism; D008565:Membrane Proteins / Q000378:metabolism*; D024101:Mitochondrial Proteins; D010713:Phosphatidylcholines / Q000737:chemistry / Q000378:metabolism; D011485:Protein Binding; D011892:Rana catesbeiana; D013050:Spectrometry, Fluorescence; D015293:Transducin; D000071256:Uncoupling Protein 1
D002352:Carrier Proteins; D005136:Eye Proteins; C034809:GNAT1 protein, human; D007473:Ion Channels; D008081:Liposomes; D008565:Membrane Proteins; D024101:Mitochondrial Proteins; D010713:Phosphatidylcholines; D000071256:Uncoupling Protein 1; D019204:GTP-Binding Proteins; D020962:Heterotrimeric GTP-Binding Proteins; D015293:Transducin