Document Detail

Identification of residues of the Saccharomyces cerevisiae G protein-coupled receptor contributing to alpha-factor pheromone binding.
MedLine Citation:
PMID:  11495900     Owner:  NLM     Status:  MEDLINE    
The Saccharomyces cerevisiae pheromone, alpha-factor (WHWLQLKPGQPMY), and Ste2p, its G protein-coupled receptor, were studied as a model for peptide ligand-receptor interaction. The affinities and activities of various synthetic position-10 alpha-factor analogs with Ste2p expressing mutations at residues Ser47 and Thr48 were investigated. All mutant receptors were expressed at a similar level in the cytoplasmic membrane, and their efficacies of signal transduction were similar to that of the wild-type receptor. Mutant receptors differed in binding affinity (Kd) and potency (EC50) for gene induction by alpha-factor. One mutant receptor (S47K,T48K) had dramatically reduced affinity and activity for [Lys10]- and [Orn10]alpha-factor, whereas the affinity for Saccharomyces kluyveri alpha-factor (WHWLSFSKGEPMY) was increased over 20-fold compared with that of wild-type receptor. In contrast, the affinity of [Lys10]- and [Orn10]alpha-factor was increased greatly in a S47E,T48E mutant receptor, whereas the binding of the S. kluyveri alpha-factor was abolished. The affinity of [Lys10]- and [Orn10]alpha-factor for the S47E,T48E receptor dropped 4-6-fold in the presence of 1 m NaCl, whereas the affinity of alpha-factor was not affected by this treatment. These results demonstrate that when bound to its receptor the 10th residue (Gln) of the S. cerevisiae alpha-factor is adjacent to Ser47 and Thr48 residues in the receptor and that the 10th residue of alpha-factors from two Saccharomyces species is responsible for the ligand selectivity to their cognate receptors. Based on these data, we have developed a two-dimensional model of alpha-factor binding to its receptor.
B K Lee; S Khare; F Naider; J M Becker
Publication Detail:
Type:  Journal Article; Research Support, U.S. Gov't, P.H.S.     Date:  2001-08-08
Journal Detail:
Title:  The Journal of biological chemistry     Volume:  276     ISSN:  0021-9258     ISO Abbreviation:  J. Biol. Chem.     Publication Date:  2001 Oct 
Date Detail:
Created Date:  2001-10-08     Completed Date:  2001-12-04     Revised Date:  2007-11-14    
Medline Journal Info:
Nlm Unique ID:  2985121R     Medline TA:  J Biol Chem     Country:  United States    
Other Details:
Languages:  eng     Pagination:  37950-61     Citation Subset:  IM    
Department of Microbiology, University of Tennessee, Knoxville, 37996, USA.
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MeSH Terms
Amino Acid Sequence
Base Sequence
Chromatography, High Pressure Liquid
DNA Primers
GTP-Binding Proteins / metabolism*
Molecular Sequence Data
Mutagenesis, Site-Directed
Peptides / metabolism*
Receptors, Cell Surface / chemistry,  genetics,  metabolism*
Saccharomyces cerevisiae / metabolism*
Signal Transduction
Grant Support
Reg. No./Substance:
0/DNA Primers; 0/Peptides; 0/Receptors, Cell Surface; 61194-02-3/mating factor; EC 3.6.1.-/GTP-Binding Proteins

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