Biomaterial Database

Immobilization and aggregation of the antimicrobial peptide protegrin-1 in lipid bilayers investigated by solid-state NMR. 2003

Jarrod J Buffy, and Alan J Waring, and Robert I Lehrer, and Mei Hong

Department of Chemistry, Iowa State University, Ames, Iowa 50011, USA.

The dynamics and aggregation of a beta-sheet antimicrobial peptide, protegrin-1 (PG-1), are investigated using solid-state NMR spectroscopy. Chemical shift anisotropies of F12 and V16 carbonyl carbons are uniaxially averaged in 1,2-dilauryl-sn-glycero-3-phosphatidylcholine (DLPC) bilayers but approach rigid-limit values in the thicker 1-palmitoyl-2-oleoyl-sn-glycerol-3-phosphatidylcholine (POPC) bilayers. The Calpha-Halpha dipolar coupling of L5 is scaled by a factor of 0.16 in DLPC bilayers but has a near-unity order parameter of 0.96 in POPC bilayers. The larger couplings of PG-1 in POPC bilayers indicate immobilization of the peptide, suggesting that PG-1 forms oligomeric aggregates at the biologically relevant bilayer thickness. Exchange NMR experiments on F12 (13)CO-labeled PG-1 show that the peptide undergoes slow reorientation with a correlation time of 0.7 +/- 0.2 s in POPC bilayers. This long correlation time suggests that in addition to aggregation, geometric constraints in the membrane may also contribute to PG-1 immobilization. The PG-1 aggregates contact both the surface and the hydrophobic center of the POPC bilayer, as determined by (1)H spin-diffusion measurements. Thus, solid-state NMR provides a wide range of information about the molecular details of membrane peptide immobilization and aggregation in lipid bilayers.

UI	MeSH Term	Description	Entries
D008051	Lipid Bilayers	Layers of lipid molecules which are two molecules thick. Bilayer systems are frequently studied as models of biological membranes.	Bilayers, Lipid,Bilayer, Lipid,Lipid Bilayer
D010767	Phosphorylcholine	Calcium and magnesium salts used therapeutically in hepatobiliary dysfunction.	Choline Chloride Dihydrogen Phosphate,Choline Phosphate Chloride,Phosphorylcholine Chloride,Choline Phosphate,Phosphocholine,Chloride, Choline Phosphate,Chloride, Phosphorylcholine,Phosphate Chloride, Choline,Phosphate, Choline
D011506	Proteins	Linear POLYPEPTIDES that are synthesized on RIBOSOMES and may be further modified, crosslinked, cleaved, or assembled into complex proteins with several subunits. The specific sequence of AMINO ACIDS determines the shape the polypeptide will take, during PROTEIN FOLDING, and the function of the protein.	Gene Products, Protein,Gene Proteins,Protein,Protein Gene Products,Proteins, Gene
D004058	Diffusion	The tendency of a gas or solute to pass from a point of higher pressure or concentration to a point of lower pressure or concentration and to distribute itself throughout the available space. Diffusion, especially FACILITATED DIFFUSION, is a major mechanism of BIOLOGICAL TRANSPORT.	Diffusions
D016880	Anisotropy	A physical property showing different values in relation to the direction in or along which the measurement is made. The physical property may be with regard to thermal or electric conductivity or light refraction. In crystallography, it describes crystals whose index of refraction varies with the direction of the incident light. It is also called acolotropy and colotropy. The opposite of anisotropy is isotropy wherein the same values characterize the object when measured along axes in all directions.	Anisotropies
D017433	Protein Structure, Secondary	The level of protein structure in which regular hydrogen-bond interactions within contiguous stretches of polypeptide chain give rise to ALPHA-HELICES; BETA-STRANDS (which align to form BETA-SHEETS), or other types of coils. This is the first folding level of protein conformation.	Secondary Protein Structure,Protein Structures, Secondary,Secondary Protein Structures,Structure, Secondary Protein,Structures, Secondary Protein
D019906	Nuclear Magnetic Resonance, Biomolecular	NMR spectroscopy on small- to medium-size biological macromolecules. This is often used for structural investigation of proteins and nucleic acids, and often involves more than one isotope.	Biomolecular Nuclear Magnetic Resonance,Heteronuclear Nuclear Magnetic Resonance,NMR Spectroscopy, Protein,NMR, Biomolecular,NMR, Heteronuclear,NMR, Multinuclear,Nuclear Magnetic Resonance, Heteronuclear,Protein NMR Spectroscopy,Biomolecular NMR,Heteronuclear NMR,Multinuclear NMR,NMR Spectroscopies, Protein,Protein NMR Spectroscopies,Spectroscopies, Protein NMR,Spectroscopy, Protein NMR
D023181	Antimicrobial Cationic Peptides	Small cationic peptides that are an important component, in most species, of early innate and induced defenses against invading microbes. In animals they are found on mucosal surfaces, within phagocytic granules, and on the surface of the body. They are also found in insects and plants. Among others, this group includes the DEFENSINS, protegrins, tachyplesins, and thionins. They displace DIVALENT CATIONS from phosphate groups of MEMBRANE LIPIDS leading to disruption of the membrane.	Cationic Antimicrobial Peptide,Cationic Antimicrobial Peptides,Cationic Host Defense Peptides,Host Defense Peptide,Microbicidal Cationic Proteins,Amphipathic Cationic Antimicrobial Peptides,Host Defense Peptides,Antimicrobial Peptide, Cationic,Antimicrobial Peptides, Cationic,Cationic Peptides, Antimicrobial,Cationic Proteins, Microbicidal,Defense Peptide, Host,Defense Peptides, Host,Peptide, Cationic Antimicrobial,Peptide, Host Defense,Peptides, Antimicrobial Cationic,Peptides, Cationic Antimicrobial,Peptides, Host Defense,Proteins, Microbicidal Cationic