The structure and organization of phospholipid bilayers as revealed by infrared spectroscopy

Fourier transform infrared (FTIR) spectroscopy is a powerful yet relatively inexpensive spectroscopic technique for studying the structure and organiz ation of phospholipid bilayers. This technique yields information about all regions of the phospholipid molecule simultaneously without the necessity of introducing perturbing extrinsic probes. In this review we summarize som e recent FTIR spectroscopic studies of the structure and organization of ph ospholipids in their lamellar liquidcrystalline, gel, and crystalline phase s and show that interconversions between these phases can be readily monito red by this technique. We also demonstrate that this technique can yield va luable information about non-lamellar phospholipid phases as well. Finally, we point out that in principle FTIR spectroscopy is capable of yielding fa irly high resolution structural and conformational information about phosph olipid molecules in multi-molecular aggregates and give several examples of how this potential is beginning to be realized. (C) 1998 Elsevier Science Ireland Ltd. All rights reserved.