Rhodopsin recognition by mutant G(s)alpha containing C-terminal residues of transducin

Michael Natochin; Khakim G Muradov; Randall L McEntaffer; Nikolai O Artemyev

doi:10.1074/jbc.275.4.2669

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Rhodopsin recognition by mutant G(s)alpha containing C-terminal residues of transducin

Journal article

Open access

Peer reviewed

Rhodopsin recognition by mutant G(s)alpha containing C-terminal residues of transducin

Michael Natochin, Khakim G Muradov, Randall L McEntaffer and Nikolai O Artemyev

The Journal of biological chemistry, Vol.275(4), pp.2669-2675

01/28/2000

DOI: 10.1074/jbc.275.4.2669

PMID: 10644728

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Abstract

The C-terminal regions of the heterotrimeric G protein alpha-subunits play key roles in selective activation of G proteins by their cognate receptors. In this study, mutant G(s)alpha proteins with substitutions by C-terminal residues of transducin (G(t)alpha) were analyzed for their interaction with light-activated rhodopsin (R*) to delineate the critical determinants of the G(t)alpha/R* coupling. In contrast to G(s)alpha, a chimeric G(s)alpha/G(t)alpha protein containing only 11 C-terminal residues from transducin was capable of binding to and being potently activated by R*. Our results suggest that Cys(347) and Gly(348) are absolutely essential, whereas Asp(346) is more modestly involved in the G(t) activation by R*. In addition, the analysis of the intrinsic nucleotide exchange in mutant G(s)alpha indicated an interaction between the C terminus and the switch II region in G(t)alpha.GDP. Mutant G(s)alpha containing the G(t)alpha C terminus and substitutions of Asn(239) and Asp(240) (switch II) by the corresponding G(t)alpha residues, Glu(212) and Gly(213), displayed significant reductions in spontaneous guanosine 5'-O-(3-thiotriphosphate)-binding rates to the levels approaching those in G(t)alpha. Communication between the C terminus and switch II of G(t)alpha does not appear essential for the activational coupling between G(t) and R*, but may represent one of the mechanisms by which Galpha subunits control intrinsic nucleotide exchange.

GTP-Binding Protein alpha Subunits, Gs - metabolism

Amino Acid Sequence

GTP-Binding Protein alpha Subunits, Gs - chemistry

Glycine - metabolism

Mutagenesis, Site-Directed

Models, Molecular

Guanosine Triphosphate - metabolism

Recombinant Fusion Proteins - chemistry

Rhodopsin - metabolism

Recombinant Fusion Proteins - metabolism

Transducin - chemistry

GTP-Binding Protein alpha Subunits, Gs - genetics

Animals

Cattle

Recombinant Fusion Proteins - genetics

Transducin - metabolism

Glutamic Acid - metabolism

Guanosine Diphosphate - metabolism

Binding Sites

Details

Title: Subtitle: Rhodopsin recognition by mutant G(s)alpha containing C-terminal residues of transducin
Creators: Michael Natochin - Department of Physiology, University of Iowa College of Medicine, Iowa City, Iowa 52242, USA
Khakim G Muradov
Randall L McEntaffer
Nikolai O Artemyev
Resource Type: Journal article
Publication Details: The Journal of biological chemistry, Vol.275(4), pp.2669-2675
DOI: 10.1074/jbc.275.4.2669
PMID: 10644728
NLM abbreviation: J Biol Chem
ISSN: 0021-9258
eISSN: 1083-351X
Publisher: United States
Grant note: DK-25295 / NIDDK NIH HHS EY-10843 / NEI NIH HHS
Language: English
Date published: 01/28/2000
Academic Unit: Molecular Physiology and Biophysics; Iowa Neuroscience Institute; Physics and Astronomy; Ophthalmology and Visual Sciences
Record Identifier: 9984025587402771

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