The Use and Misuse of FTIR Spectroscopy in the Determination of Protein Structure

Abstract

Fourier transform infrared (FTIR) spectroscopy is an established tool for the structural characterization of proteins. However, many potential pitfalls exist for the unwary investigator. In this review we critically assess the application of FTIR spectroscopy to the determination of protein structure by (1) outlining the principles underlying protein secondary structure determination by FTIR spectroscopy, (2) highlighting the situations in which FTIR spectroscopy should be considered the technique of choice, (3) discussing the manner in which experiments should be conducted to derive as much physiologically relevant information as possible, and (4) outlining current methods for the determination of secondary structure from infrared spectra of proteins.

Implantable amyloid hydrogels for promoting stem cell differentiation to neurons

“…Because aggregates of amyloid protein and peptide consist of a cross-β-sheet-rich structure, 11,27 the secondary structure of the peptides in the hydrogels was assessed using FTIR spectroscopy. 28 The FTIR peaks at approximately 1630 and 1690 cm − 1 in the amide I (1600-1700 cm − 1 ) region confirmed the presence of cross β-sheet structures in the gel (Figure 2g and Supplementary Figure S4). …”

Retention of Native Protein Structures in the Absence of Solvent: A Coupled Ion Mobility and Spectroscopic Study

“…For both 8+ ions, the amide‐II bands are found around 1525 cm −1 , a value that is typical for proteins in the condensed phase 10. The amide‐I band for myoglobin 8+ is roughly symmetrical and has a maximum at 1655 cm −1 , which is typical for a helical secondary structure 10.…”

“…The amide‐I band for myoglobin 8+ is roughly symmetrical and has a maximum at 1655 cm −1 , which is typical for a helical secondary structure 10. The IR spectrum of β‐lactoglobulin in the 8+ charge state, on the other hand, exhibits a rather different signature.…”

Raman spectroscopy and multivariate analysis for the rapid discrimination between native-like and non-native states in freeze-dried protein formulations

“…Changes in the distribution of secondary structures of freeze-dried proteins are most commonly assessed by visual comparison of the second derivative of the amide I band (1700-1600 cm -1 ) in the blank corrected FTIR spectra of the sample with a native reference spectrum [10,15,25,26,27,28,29,30]. Freeze-dried formulations were designated as NL if the amide I spectrum was similar (in secondary structural elements distribution) to that of the native LDH before freeze-drying (Fig.…”