Basic Aspects of the Technique and Applications of Infrared Spectroscopy of Peptides and Proteins

Abstract

Infrared spectroscopy is being increasingly utilized for the analysis of peptides and proteins because it probes the universally available amide (peptide) bonds, which display distinct IR signals for differently folded peptides and proteins. Other spectroscopic techniques useful for studying protein structures in solutions are circular dichroism (CD), ultraviolet absorption and fluorescence spectroscopy, Raman and nuclear magnetic resonance (NMR). Among the techniques for secondary structure, NMR and Raman spectroscopy need unusually high concentration of proteins, and NMR analysis is still limited to small proteins of about 200 amino acid residues. CD analysis is limited to clear protein solution (as opposed to membrane proteins) due to the problem with light scattering. Furthermore, for estimation of secondary structure of protein by CD accurate protein concentration is needed. Infrared spectroscopy is an emerging technique for protein analysis. Amide I, II and III are most commonly used IR spectral regions used for protein structure-function analysis. Recent advances in the development of instrumentation (Fourier transformation, sampling), protein IR data bank (band assignments to different components of secondary structure), and techniques (two-dimensional IR methods, time-resolution, and isotopic labeling) have significantly augmented IR spectroscopy as an analytical tool for peptides and proteins. This chapter provides an overview of the basic technique and some of the applications of IR spectroscopy to examine structure, interaction, and conformational changes in peptides and proteins.

Circular dichroism and infrared spectroscopic characterization of secondary structure components of protein Z during mashing and boiling processes

“…Moreover, regions of helices transformed into random coil elements. The structural investigations on protein Z from FTIR spectra showed the same alterations as observed in the CD data (Singh, 2000).…”

“…The conformational amide I region in the range of 1700-1600 cm À1 of the FTIR spectrum can be used to reveal the secondary structure of proteins (Barth, 2007). Combined with deconvolution and curve-fitting of the amide I region, the secondary structural compositions of proteins can be predicted (Singh, 2000).…”

Sustainable Production of Carbon Fiber: Effect of Cross-Linking in Wool Fiber on Carbon Yields and Morphologies of Derived Carbon Fiber

“…The spectrum of wool fiber shows a peak at 1043 cm −1 for cysteic acid, 1626 cm −1 for amide I, 1531 cm −1 for amide II, and 1230 cm −1 for amide III. 23 There is a broad peak at 3100 to 3400 cm…”

Automatic amide I frequency selection for rapid quantification of protein secondary structure from Fourier transform infrared spectra of proteins

“…This includes methods that can be used for accurately quantifying protein secondary structure. The work done in quantifying protein secondary structure from FTIR spectra of proteins along with its strengths and weaknesses has been thoroughly reviewed [2][3][4][5][6][7]. Most work has been done using a curve fitting approach which basically relies on band narrowing and decomposition of mostly the amide I band shape into its underlying components [5,[8][9][10][11][12][13][14][15][16][17][18][19][20][21][22][23].…”

“…The work done in quantifying protein secondary structure from FTIR spectra of proteins along with its strengths and weaknesses has been thoroughly reviewed [2][3][4][5][6][7]. Most work has been done using a curve fitting approach which basically relies on band narrowing and decomposition of mostly the amide I band shape into its underlying components [5,[8][9][10][11][12][13][14][15][16][17][18][19][20][21][22][23]. More recently, pattern recognition based methods have been suggested [24][25][26][27][28][29][30][31][32][33][34][35].…”