| Title: | "Synthesis, biological activity, and conformational analysis of peptidomimetic analogues of the Saccharomyces cerevisiae alpha-factor tridecapeptide" |
| Author(s): | Zhang YL; Marepalli HR; Lu HF; Becker JM; Naider F; |
| Address: | "Department of Chemistry, The College of Staten Island, The Graduate School of The City University of New York 10314, USA" |
| ISSN/ISBN: | 0006-2960 (Print) 0006-2960 (Linking) |
| Abstract: | "Biochemical and biophysical investigations on the Saccharomyces cerevisiae alpha-factor indicate that this tridecapeptide mating pheromone (WHWLQLKPGQPMY) might adopt a type II beta-turn in the center of the peptide when it binds to its G protein-coupled receptor. To test this hypothesis we synthesized analogues of alpha-factor incorporating a (R or S)-gamma-lactam conformational constraint [3-(R or S)-amino-2-oxo-1-pyrrolidineacetamido] in place of the Pro-Gly at residues 8 and 9 of the peptide and tested their biological activities and receptor binding. Analogues were purified to >99% homogeneity as evidenced by high-performance liquid chromatography and capillary electrophoresis and characterized by amino acid analysis, mass spectrometry, and nuclear magnetic resonance (NMR) spectroscopy. The restricted alpha-factor analogue WHWLQLK[(R)-gamma-lactam]QP[Nle]Y was more active than its lactam-containing diastereomeric homologue WHWLQLK[(S)-gamma-lactam]QP[Nle]Y and about equally active with the [Nle12]-alpha-factor in growth arrest and FUS1-lacZ gene induction assays. Both lactam analogues competed with tritiated [Nle12]-alpha-factor for binding to the alpha-factor receptor (Ste2p) with the (R)-gamma-lactam-containing peptide having 7-fold higher affinity than the (S)-gamma-lactam-containing homologue. Two-dimensional NMR spectroscopy and modeling analysis gave evidence that the (R)-gamma-analogue is a flexible peptide that assumes a transient gamma-turn structure around the lactam moiety. The results represent the first example of an alpha-factor analogue containing a peptidomimetic constraint that is as active as the native pheromone. The correlation between activity and structure provides further evidence that the biologically active conformation of the molecule contains a turn in the middle of the pheromone. This study provides new insights into the structural basis of alpha-factor activity and adds to the repertoire of conformationally biasing constraints that can be used to maintain and even enhance biological activity in peptide hormones" |
| Keywords: | "Amides Amino Acids/chemistry Circular Dichroism Growth Inhibitors/metabolism Lactams/metabolism Mating Factor *Molecular Mimicry Nuclear Magnetic Resonance, Biomolecular Peptides/*chemical synthesis/chemistry/metabolism Pheromones/*chemical synthesis/chem;" |
| Notes: | "MedlineZhang, Y L Marepalli, H R Lu, H F Becker, J M Naider, F eng GM-22086/GM/NIGMS NIH HHS/ GM-22087/GM/NIGMS NIH HHS/ Research Support, Non-U.S. Gov't Research Support, U.S. Gov't, Non-P.H.S. Research Support, U.S. Gov't, P.H.S. 1998/09/09 Biochemistry. 1998 Sep 8; 37(36):12465-76. doi: 10.1021/bi980787u" |
