http://www.bio21.bas.bg/ibf/PC_review.pdf

Phases and phase transitions of the phosphatidylcholines

Infrared spectroscopy is a useful technique for the determination of conformation and orientation of membrane-associated proteins and lipids. The technique is especially powerful for detecting conformational changes by recording spectral differences before and after perturbations in physiological solution. Polarized infrared measurements on oriented membrane samples have revealed valuable information on the orientation of chemical groupings and substructures within membrane molecules which is difficult to obtain by other methods. The application of infrared spectroscopy to the static and dynamic structure of proteins and peptides in lipid bilayers is reviewed with some emphasis on the importance of sample preparation. Limitations of the technique with regard to the absolute determination of secondary structure and orientation and new strategies for structural assignments are also discussed.

http://shaker.umh.es/docencia/doctorado_IR/FTIR_review3.pdf

Infrared spectroscopy of proteins and peptides in lipid bilayers

Molecular mechanism of membrane permeabilization by the peptide antibiotic surfactin.

Molecular dynamics simulations of fully hydrated pure bilayers of four widely studied phospholipids, 1,2-dilauroyl-sn-glycero-3-phosphocholine (DLPC), 1,2-dimyristoyl-sn-glycero-3-phosphocholine (DMPC), 1,2-dioleoyl-sn-glycero-3-phosphocholine (DOPC), and 2-oleoyl-1-palmitoyl-sn-glycero-3-phosphocholine (POPC) using a recent revision of the GROMOS96 force field are reported. It is shown that the force field reproduces the structure and the hydration of bilayers formed by each of the four lipids with high accuracy. Specifically, the solvation and the orientation of the dipole of the phosphocholine headgroup and of the ester carbonyls show that the structure of the primary hydration shell in the simulations closely matches experimental findings. This work highlights the need to reproduce a broad range of properties beyond the area per lipid, which is poorly defined experimentally, and to consider the effect of system size and sampling times well beyond those commonly used.

On the validation of molecular dynamics simulations of saturated and cis-monounsaturated phosphatidylcholine lipid bilayers: A comparison with experiment

Infectious disease is a critically important global healthcare issue. In the U.S. alone there are 2 million new cases of hospital-acquired infections annually leading to 90,000 deaths and 5 billion dollars of added healthcare costs. Couple these numbers with the appearance of new antibiotic resistant bacterial strains and the increasing occurrences of community-type outbreaks, and clearly this is an important problem. Our review attempts to bridge the research areas of natural host defense peptides (HDPs), a component of the innate immune system, and biocidal cationic polymers. Recently discovered peptidomimetics and other synthetic mimics of HDPs, that can be short oligomers as well as polymeric macromolecules, provide a unique link between these two areas. An emerging class of these mimics are the facially amphiphilic polymers that aim to emulate the physicochemical properties of HDPs but take advantage of the synthetic ease of polymers. These mimics have been designed with antimicrobial activity and, importantly, selectivity that rivals natural HDPs. In addition to providing some perspective on HDPs, selective mimics, and biocidal polymers, focus is given to the arsenal of biophysical techniques available to study their mode of action and interactions with phospholipid membranes. The issue of lipid type is highlighted and the important role of negative curvature lipids is illustrated. Finally, materials applications (for instance, in the development of permanently antibacterial surfaces) are discussed as this is an important part of controlling the spread of infectious disease.

/pdf/infectious-disease-connecting-innate-immunity-to-biocidal-2uonocayga.pdf

Infectious disease: Connecting innate immunity to biocidal polymers

Components of the carbonyl stretching band in the infrared spectra of hydrated 1,2-diacylglycerolipid bilayers: a reevaluation.

The interfacial structure of phospholipid bilayers: differential scanning calorimetry and Fourier transform infrared spectroscopic studies of 1,2-dipalmitoyl-sn-glycero-3-phosphorylcholine and its dialkyl and acyl-alkyl analogs

W. Pohle

Papers

Components of the carbonyl stretching band in the infrared spectra of hydrated 1,2-diacylglycerolipid bilayers: a reevaluation.

The interfacial structure of phospholipid bilayers: differential scanning calorimetry and Fourier transform infrared spectroscopic studies of 1,2-dipalmitoyl-sn-glycero-3-phosphorylcholine and its dialkyl and acyl-alkyl analogs