Infrared reflection-absorption spectroscopy of lipids, peptides, and proteins in aqueous monolayers
2002; Elsevier BV; Linguagem: Inglês
10.1016/s1063-5823(02)52005-6
ISSN1063-5823
AutoresRichard Mendelsohn, Carol R. Flach,
Tópico(s)Photoreceptor and optogenetics research
ResumoInfrared reflection-absorption spectroscopy (IRRAS) provides a unique means of monitoring the chain conformation and orientation of lipids as well as the secondary structure and orientation of peptides and proteins in situ in monolayers at the air/water interface. This chapter describes the experimental approaches and instrumentation used to acquire IRRAS spectra. Spectra-structure correlations are reviewed. Several applications of the technique are discussed, including determinations of lipid chain conformation, lipid headgroup interactions, and protein and peptide secondary structure. Whereas the measured IRRAS frequencies may be correlated with molecular structure information in the usual way, determination of molecular orientation requires a detailed analysis of the reflected light intensities. Simulations included in this chapter show that the infrared (IR) bands may be distorted from their transmission spectroscopy bandshapes, especially when measurements are made at angles of incidence near the Brewster angle. The measured intensities have been quantitatively used to monitor the tilt angle of the hydrophobic pulmonary surfactant protein SP-C in lipid monolayers. Additional applications to peptide orientation are reviewed.
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