Biomedical subjects

Tim Salditt

Publications and source records attributed to Tim Salditt.

4 recordsLinked to original sources

PubMed2003

Short range order of hydrocarbon chains in fluid phospholipid bilayers studied by x-ray diffraction from highly oriented membranes.

We present a study of the short range ordering of hydrocarbon chains in phospholipid bilayers. The x-ray peak associated with the hydrocarbon chains has been probed by means of reciprocal space mappings. Using 20 keV undulator radiation and samples of negligible mosaicity (orientational disorder), the intensity distribution is probed as a function of two coordinates, the momentum transfer parallel and perpendicular to the bilayer, over a wide range and at high resolution. Structural results are obtained concerning the distribution of tilted segments, the correlation length and the radial distribution function of the quasi two-dimensional liquid structure. A comparison is made with published molecular dynamics data (H. Heller, M. Schaefer, and K. Schulten. 1993. J. Phys. Chem. 97:8343-8360) by direct Fourier transformation of the atomic coordinates. The exact prefactor in the relationship between interchain distance and peak position is derived.

Biophysical Phenomena↗

PubMed2003

Lipid-peptide interaction in oriented bilayers probed by interface-sensitive scattering methods.

Oriented lipid membranes deposited on solid substrates offer unique experimental opportunities to study lipid bilayer structure and lipid-peptide interaction in suitable model systems. In particular, modern interface-sensitive X-ray and neutron scattering methods can be used to probe the short-range order and molecular conformations of peptides and lipids in the fluid state of the bilayer.

Animals↗

PubMed2002

Magainin 2 in phospholipid bilayers: peptide orientation and lipid chain ordering studied by X-ray diffraction.

We present a structural study of biomimetic lipid bilayers interacting with the antimicrobial peptide magainin 2 amide, using grazing incidence X-ray diffraction and reciprocal space mapping (RSM) techniques. The short-range order of lipid chains in lecithin is found to be strongly reduced by the peptides. From the scattering intensity of the chain correlation peak, we can quantify the lateral length scale R over which the bilayer structure is affected by peptide binding. The non-local perturbation of the bilayer is discussed in the framework of bilayer elasticity theory.

Amino Acid Sequence↗

PubMed2002

Layer-by-layer self-assembly of supramolecular and biomolecular films.

In this paper, we give a short account on recent studies of layer-by-layer self-assembly of supramolecular and biomolecular films. Such films are built up from layers of macro-ions with opposing charge. A simple film can be obtained by alternating the adsorption of two components: a flexible, synthetic polycation chains and a supramolecular or biomolecular moiety. We focus on three examples, in which the second component consists either of a supramolecular metal-organic complex (MOC), a nucleic acid, or a biological membrane patch (purple membrane). While the flexible polvcation chains (as well as eventual annealing layers) ensure a uniform build-up of the chain, the second macromolecular component may be used to functionalize the films. The combination of layer-by-layer self-assembly and biotechnologically relevant macromolecules may lead to new devices or biomaterial applications. To this end, precise studies of the deposition process and the film structure are needed. Here, we focus on interface sensitive scattering techniques for the structural analysis.

Adsorption↗