Biomaterial Database

Interfacial interactions between poly[L-lysine]-based branched polypeptides and phospholipid model membranes. 2003

R Szabó, and F Hudecz, and F Reig

Research Group Peptide Chemistry at Eötvös L. University, Hungarian Academy of Sciences, P.O. Box 32, H-1518 Budapest 112, Hungary.

The interaction of five poly[L-lysine]-derived branched chain polypeptides of poly[Lys(X(i))] (X(i)K) or poly[Lys(X(i)-DL-Ala(m))] (XAK) with lipid bilayers (DPPC and DPPC/PG, 8:2) was studied by fluorescence polarization techniques. Two fluorescent probes, DPH and TMA-DPH, were utilized to monitor changes of motion in the internal and/or in the polar head regions, respectively. Results indicate that the interaction of polypeptides with neutral (DPPC) bilayers is mainly dependent on the polarity and electrical charge of side chains. The amphoteric E(i)K shows the highest level of interaction. Polycationic polypeptides (H(i)K, P(i)K, TAK) have a relatively small effect on the transition temperature of the lipids, while the polyanionic Succ-EAK has no effect at the alkyl chain region of the bilayer. Data with TMA-DPH indicate the lack of pronounced interaction between the polypeptides and the outer surface of the liposome. Similar tendency was documented for DPPC/PG vesicles. Polypeptides, H(i)K, and P(i)K induce significant changes in the transition temperature, thus indicating their insertion into the hydrophobic core of the bilayer without marked effect on the polar head region. Results suggest that these polypeptides (except E(i)K) have no destabilizing effect on liposomes studied. These properties are considered as beneficial for their use as safe carriers for bioactive molecules.

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
D008563	Membrane Lipids	Lipids, predominantly phospholipids, cholesterol and small amounts of glycolipids found in membranes including cellular and intracellular membranes. These lipids may be arranged in bilayers in the membranes with integral proteins between the layers and peripheral proteins attached to the outside. Membrane lipids are required for active transport, several enzymatic activities and membrane formation.	Cell Membrane Lipid,Cell Membrane Lipids,Membrane Lipid,Lipid, Cell Membrane,Lipid, Membrane,Lipids, Cell Membrane,Lipids, Membrane,Membrane Lipid, Cell,Membrane Lipids, Cell
D010455	Peptides	Members of the class of compounds composed of AMINO ACIDS joined together by peptide bonds between adjacent amino acids into linear, branched or cyclical structures. OLIGOPEPTIDES are composed of approximately 2-12 amino acids. Polypeptides are composed of approximately 13 or more amino acids. PROTEINS are considered to be larger versions of peptides that can form into complex structures such as ENZYMES and RECEPTORS.	Peptide,Polypeptide,Polypeptides
D010743	Phospholipids	Lipids containing one or more phosphate groups, particularly those derived from either glycerol (phosphoglycerides see GLYCEROPHOSPHOLIPIDS) or sphingosine (SPHINGOLIPIDS). They are polar lipids that are of great importance for the structure and function of cell membranes and are the most abundant of membrane lipids, although not stored in large amounts in the system.	Phosphatides,Phospholipid
D011107	Polylysine	A peptide which is a homopolymer of lysine.	Epsilon-Polylysine,Poly-(Alpha-L-Lysine),Epsilon Polylysine
D005454	Fluorescence Polarization	Measurement of the polarization of fluorescent light from solutions or microscopic specimens. It is used to provide information concerning molecular size, shape, and conformation, molecular anisotropy, electronic energy transfer, molecular interaction, including dye and coenzyme binding, and the antigen-antibody reaction.	Anisotropy, Fluorescence,Fluorescence Anisotropy,Polarization, Fluorescence,Anisotropies, Fluorescence,Fluorescence Anisotropies,Fluorescence Polarizations,Polarizations, Fluorescence
D013499	Surface Properties	Characteristics or attributes of the outer boundaries of objects, including molecules.	Properties, Surface,Property, Surface,Surface Property
D013696	Temperature	The property of objects that determines the direction of heat flow when they are placed in direct thermal contact. The temperature is the energy of microscopic motions (vibrational and translational) of the particles of atoms.	Temperatures