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기타논문
Date: September 2001

Journal: Molecular Cell Biology Research Communications Volume 4, Issue 5, 2001, Pages 282-291 , Doi: 10.1006/mcbr.2001.0293

2001 | An intramolecular contact in Gα transducin that participates in maintaining its intrinsic GDP release rate…

Thomas, T.O.a, Bae, H.b, Medkova, M.a, Hamm, H.E.ac

Abstract

Receptor mediated stimulation of the G protein-α subunit leads to exchange of GDP for GTP, activating the protein, Spontaneous GDP release from Gα can also lead to the active state, if GTP in solution binds the nucleotide binding pocket. The purpose of this study is to evaluate the molecular determinants for maintaining the spontaneous GDP release rates between two Gα subunits, Gαt has a low rate of nucleotide release, compared to Gαi1, Gαti1, chimeras were used to explore the molecular basis for this behavior, The C-terminal α4-helix, the N-terminal 56 residues and the Switch l/II regions of Gαt were shown to affect the low spontaneous GDP release rate in Gαt. A specific molecular contact between Asp26 and Asn191 was found in Gαt that is not present in Gαi1. In two chimeras disrupting this interaction produced an increased spontaneous GDP release; restoring the contact present in Gαt into these chimeras decreased the GDP release rate by half as compared to the original chimeras. Similarly, introduction of this contact in wild-type Gαi1 decreased the GDP release rate of Gαi1 by half. Differences in GDP release rates may reflect physiological roles these proteins play in living systems. © 2001 Academic Press.


Author keywords

G protein; Intrinsic fluorescence; Spontaneous GDP release; Transducin


Indexed keywords

EMTREE drug terms: asparagine; aspartic acid; guanosine diphosphate; nucleotide; protein subunit; transducin

EMTREE medical terms: alpha helix; amino terminal sequence; article; carboxy terminal sequence; chimera; fluorescence; molecular interaction; nucleotide sequence; priority journal; protein secretion; chemical structure; chemistry; Escherichia coli; genetics; kinetics; metabolism; point mutation; protein conformation; protein tertiary structure; signal transduction; X ray crystallography

MeSH: Chimera; Crystallography, X-Ray; Escherichia coli; Fluorescence; Guanosine Diphosphate; Kinetics; Models, Molecular; Point Mutation; Protein Conformation; Protein Structure, Tertiary; Signal Transduction; Transducin
Medline is the source for the MeSH terms of this document.


Chemicals and CAS Registry Numbers: Guanosine Diphosphate, 146-91-8; Transducin, EC 3.6.1.-


ISSN: 15224724 CODEN: MCBCFSource Type: Journal Original language: English
DOI: 10.1006/mcbr.2001.0293 PubMed ID: 11529678 Document Type: Article
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