NMR studies of the alpha-mating factor from the yeast Saccharomyces cerevisiae in solution and in the presence of lipid vesicles.
Item
-
Title
-
NMR studies of the alpha-mating factor from the yeast Saccharomyces cerevisiae in solution and in the presence of lipid vesicles.
-
Identifier
-
AAI8914765
-
identifier
-
8914765
-
Creator
-
Jelicks, Linda Ann.
-
Contributor
-
Adviser: Michelle S. Broido
-
Date
-
1988
-
Language
-
English
-
Publisher
-
City University of New York.
-
Subject
-
Chemistry, Biochemistry | Chemistry, Physical
-
Abstract
-
The alpha-mating factor is a tridecapeptide pheromone ({dollar}\sp+{dollar}NH{dollar}\sb3{dollar}-Trp{dollar}\sp1{dollar}-His{dollar}\sp2{dollar}-Trp{dollar}\sp3{dollar}-Leu{dollar}\sp4{dollar}-Gln{dollar}\sp5{dollar}-Leu{dollar}\sp6{dollar}-Lys{dollar}\sp7{dollar}-Pro{dollar}\sp8{dollar}-Gly{dollar}\sp9{dollar}-Gln{dollar}\sp{10}{dollar}-Pro{dollar}\sp{11}{dollar}-Met{dollar}\sp{12}{dollar}-Tyr{dollar}\sp{13}{dollar}-COOH), secreted by the {dollar}\alpha{dollar}-cells of the yeast Saccharomyces cerevisiae, which interacts with a membrane-bound receptor on a-cells and elicits hormone-like responses necessary for mating of the two different haploid cell types ({dollar}\alpha{dollar} and a). A number of biochemical and biophysical techniques have been used to study the structure and activity of this peptide. The NMR techniques utilized here provide a direct method for determining alpha-factor conformations in solution and in the lipid-bound state which are then correlated with biological activity.;Acquisition of two dimensional nuclear Overhauser effect (NOESY) spectra of the peptide in organic solvent (DMSO) and rotating frame nuclear Overhauser effect (ROESY) spectra in aqueous solution suggest the presence of a Type II beta-turn spanning residues 7-10 but no other preferred conformations. NOESY spectra acquired in the presence of lipid vesicles indicate that this turn is stabilized by the interaction with lipid. Furthermore, the lipid induces a compact folded structure at the N-terminus of the peptide. In addition to these two-dimensional studies, results obtained for binding to several different lipids indicate that the peptide-lipid interaction is both electrostatic and hydrophobic in nature.;Effects of the peptide on the phospholipid vesicles were studied by {dollar}\sp{lcub}31{rcub}{dollar}P and {dollar}\sp2{dollar}H NMR and by quasielastic light scattering. The peptide induces an increase in vesicle size, appears to interact preferentially with the liquid crystalline state lipid relative to the gel state lipid, and imparts rigidity into this fluid lipid state. These effects are similar to those described in the literature for a number of membrane-active peptides.;Both the solution and lipid-bound conformations of the alpha-factor indicated by the 2D NOE studies are different from those proposed by other investigators who do not detect the beta-turn.
-
Type
-
dissertation
-
Source
-
PQT Legacy CUNY.xlsx
-
degree
-
Ph.D.
