From structure to cellular mechanism with infrared microspectroscopy

Abstract

Current efforts in structural biology aim to integrate structural information within the context of cellular organization and function. X-rays and infrared radiation stand at opposite ends of the electromagnetic spectrum and act as complementary probes for achieving this goal. Intense and bright beams are produced by synchrotron radiation, and are efficiently used in the wavelength domain extending from hard X-rays to the far-infrared (or THz) regime. While X-ray crystallography provides exquisite details on atomic structure, Fourier transform infrared microspectroscopy (FTIRM) is emerging as a spectroscopic probe and imaging tool for correlating molecular structure to biochemical dynamics and function. In this manuscript, the role of synchrotron FTIRM in bridging the gap towards ‘functional biology’ is discussed based upon recent achievements, with a critical assessment of the contributions to biological and biomedical research.

Multivariate Analysis for Fourier Transform Infrared Spectra of Complex Biological Systems and Processes

“…In this way, FTIR microspectroscopy provides detailed information on several biological processes in situ, among which stem cell differentiation [1][2][3][4][5], somatic cell reprogramming [6], cell maturation [7,8], amyloid aggregation [9][10][11][12] and cancer onset and progression [13][14][15], making it possible to disclose the infrared response not only from single cells, but also from subcellular compartments [8,16,17].…”

Effect of protein secondary structures in mixed feedstuff detected by Fourier transform infrared spectroscopy on ruminal protein degradation kinetics

“…The FTIR spectrum of protein has two prominent features, the amide I (1600-1700 cm -1 ) and amide II (1500-1560 cm -1 ) bands, which arise primarily from the C=O and C-N stretching vibrations of the peptide backbone, respectively (Haris and Severcan 1999). FTIR has been shown to be particularly sensitive to protein secondary structure based on the vibrational frequency of the amide I (C=O) band, which is affected by different hydrogen-bonding environments for α-helix, β-sheet, β-turn, and random coil (Miller and Dumas 2010). Until the nineties, the quality of FTIR increased gradually to reach extremely good signal-to-noise ratios (Goormaghtigh et al 2009).…”

Fourier Transform Infrared Microspectroscopy as a Tool for Embryonic Stem Cell Studies

“…Indeed, due to its radiation source 100-1000 times brighter than that of a conventional thermal one, it is possible to collect an infrared absorption spectrum at a higher spatial resolution from a sample area of only few microns. In this way, a synchrotron IR source enables to collect high signal -to -noise ratio spectra of subcellular compartments, providing better insights useful for the study of biological processes within single cells (Miller & Dumas, 2010). We should recall that -even if samples in different physical states can be examined by FTIR spectroscopy -the sample condition can strongly affect the FTIR spectra.…”

“…Thanks to the use of an infrared microscope coupled to a FTIR spectrometer, it becomes possible to collect the absorption spectrum from a selected sample area. Interestingly, these techniques, thank to their fasttime resolution, have been successfully used to snapshot and "freeze" molecular events in complex systems (Miller & Dumas, 2010;Hamm, 2009). …”

“…Indeed, these vibrational approaches have been shown to be a promising tool for the characterization of cellular mechanisms, providing not only structural information, but also details on the dynamics of the structures (Miller & Dumas, 2010). Concerning in particular the study of complex biological systems, it is important to underline that the multivariate statistical analysis is an essential support to fully understand the spectroscopic response.…”