Tantry S, et al. (2010) Binding of fluorinated phenylalanine alpha-factor analogues to Ste2p: evidence for a cation-pi binding interaction between a peptide ligand and its cognate G protein-coupled receptor. Biochemistry 49(24):5007-15
Abstract: Ste2p, a G protein-coupled receptor (GPCR), binds alpha-factor, WHWLQLKPGQPMY, a tridecapeptide pheromone secreted by yeast cells. Upon alpha-factor binding, Ste2p undergoes conformational changes activating a signal transduction system through its associated heterotrimeric G protein leading to the arrest of cell growth in the G1 phase to prepare cells for mating Previous studies have indicated that Tyr at position-13 of alpha-factor interacts with Arg58 on transmembrane one (TM1) of Ste2p. This observation prompted this investigation to determine whether a cation-pi type interaction occurred between these residues. Tyrosine at position-13 of alpha-factor was systematically substituted with analogous amino acids with varying cation-pi binding energies using solid phase peptide synthesis, and these analogs were modified by derivitization of their Lys7 residue with the fluorescent group 7-nitrobenz-2-oxa-1,3-diazole (NBD) to serve as a useful probe for binding determination. Saturation binding of these peptides to Ste2p was assayed using whole yeast cells and a flow cytometer. In parallel the biological activities of the peptides were determined using a growth arrest assay. The data provide evidence for the presence of a cation-pi interaction between Arg58 of Ste2p and Tyr13 of alpha-factor.
|Status: Published||Type: Journal Article||PubMed ID: 20420459|
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