The research proposed in this application is carried out with the objective of obtaining basic information which can be used to build an understanding, in molecular terms, of physiologically important biological membrane phenomena. Work is centered on the continuing investigation of the interactions between lipids in multicomponent bilayers and between lipid and protein components in these systems. Of special interest are multicomponent bilayers exhibiting compositional domain structure either within the plane of the bilayer or between its apposing faces. The research is specifically aimed at answering the following questions. a) What are the physical and biologically relevant properties of multicomponent bilayers with in-plan compositional domains? b) What are the physical and biologically relevant properties of multicomponent bilayers with different compositions in the two constituent monolayers? c) What are the thermodynamic and kinetic parameters governing the insertion of hydrophobic peptides into multicomponent bilayers as assessed by bilayer interaction with semi-synthetic proteins formed from hydrophobic peptides linked to bovine pancreatic trypsin inhibitor? The bilayer systems employed in this study are primarily unilamellar vesicles with radii greater than 400A and planar oriented multibilayers. Glycerol-based lipids are of central concern. Interactant proteins are formed by linking synthetic hydrophobic peptides to a carrier protein, bovine pancreatic trypsin inhibitor. Assessment of the parameters governing interactions between components and the properties of compositional domain systems will depend upon a variety of physical techniques. These include the use of fluorescent probes, NMR spectroscopy (1H, 2H, 13C, and 31P), ESR spectroscopy, differential scanning calorimetry and the use of hydrodynamic and equilibrium methods to characterize vesicle dispersions. The studies outlined in this proposal depend critically not only on physical techniques but also on analytical techniques long in use in this laboratory and on the established capacity of the laboratory to synthesize, prepare from natural sources, and modify chemically a wide variety of membrane lipids.

Agency
National Institute of Health (NIH)
Institute
National Institute of General Medical Sciences (NIGMS)
Type
Research Project (R01)
Project #
5R01GM014628-29
Application #
2169165
Study Section
Biophysical Chemistry Study Section (BBCB)
Project Start
1977-05-01
Project End
1996-04-30
Budget Start
1994-05-01
Budget End
1995-04-30
Support Year
29
Fiscal Year
1994
Total Cost
Indirect Cost
Name
University of Virginia
Department
Biochemistry
Type
Schools of Medicine
DUNS #
001910777
City
Charlottesville
State
VA
Country
United States
Zip Code
22904
Sankaram, M B; Jones, J D (1994) Mode of membrane interaction of wild-type and mutant signal peptides of the Escherichia coli outer membrane protein A. J Biol Chem 269:23477-83
Sankaram, M B; Marsh, D; Gierasch, L M et al. (1994) Reorganization of lipid domain structure in membranes by a transmembrane peptide: an ESR spin label study on the effect of the Escherichia coli outer membrane protein A signal peptide on the fluid lipid domain connectivity in binary mixtures of dimyristoy Biophys J 66:1959-68
Moll, T S; Thompson, T E (1994) Semisynthetic proteins: model systems for the study of the insertion of hydrophobic peptides into preformed lipid bilayers. Biochemistry 33:15469-82
Almeida, P F; Vaz, W L; Thompson, T E (1993) Percolation and diffusion in three-component lipid bilayers: effect of cholesterol on an equimolar mixture of two phosphatidylcholines. Biophys J 64:399-412
Almeida, P F; Vaz, W L; Thompson, T E (1992) Lateral diffusion and percolation in two-phase, two-component lipid bilayers. Topology of the solid-phase domains in-plane and across the lipid bilayer. Biochemistry 31:7198-210
Sankaram, M B; Thompson, T E (1992) Deuterium magnetic resonance study of phase equilibria and membrane thickness in binary phospholipid mixed bilayers. Biochemistry 31:8258-68
Melo, E C; Lourtie, I M; Sankaram, M B et al. (1992) Effects of domain connection and disconnection on the yields of in-plane bimolecular reactions in membranes. Biophys J 63:1506-12
Sankaram, M B; Marsh, D; Thompson, T E (1992) Determination of fluid and gel domain sizes in two-component, two-phase lipid bilayers. An electron spin resonance spin label study. Biophys J 63:340-9
Wimley, W C; Thompson, T E (1991) Phosphatidylethanolamine enhances the concentration-dependent exchange of phospholipids between bilayers. Biochemistry 30:4200-4
Sankaram, M B; Thompson, T E (1991) Cholesterol-induced fluid-phase immiscibility in membranes. Proc Natl Acad Sci U S A 88:8686-90

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