Light scattering, protein structure analysis using

A hindrance to the elucidation of membrane structure is, of course, the material itself. Membranes are rather intractable lipoprotein systems. Their lipid, protein, and carbohydrate contents are variable both quantitatively and qualitatively since they cannot be crystallized, a detailed analysis by x-ray diffraction is impossible, and since they do not form solutions, the use of hydrodynamic or light-scattering techniques is quite limited. Electron microscopy has been the major physical method, but it is becoming increasingly clear that the electron microscope, at least at present, is incapable by itself of clarifying membrane structure on the molecular level (47). Despite an extensive literature, there is no general... 

FT-IR spectroscopy is particularly useful for probing the structure of membrane proteins. Until recently, a lack of adequate experimental techniques has been the reason for the poor understanchng of the secondary structure of most membrane proteins. X-ray diffraction requires high quality crystals and these are not available for many membrane proteins. Circular dichroism (CD) has been widely used for studying the conformation of water-soluble proteins, but problems arise in its use for membrane proteins. The light scattering effect may distort CD spectra and lead to substantial errors in their interpretation. In addition, the reference spectra used for the analysis of CD spectra are based on globular proteins in aqueous solution and may not be applicable to membrane proteins in the hydrophobic environment of lipid bilayers. 

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