Dear friend Yakoub Ladjal Ettoumi

There are many analytical techniques that can be combined with FTIR to comprehensively characterize a protein. Some commonly used techniques include:

1. X-ray crystallography or small-angle X-ray scattering (SAXS) to determine the 3D structure of the protein

2. Nuclear magnetic resonance (NMR) spectroscopy to study protein dynamics and conformational changes

3. Differential scanning calorimetry (DSC) or thermogravimetric analysis (TGA) to investigate the thermal stability and unfolding of the protein

4. Circular dichroism (CD) spectroscopy to study the secondary structure of the protein

5. Size-exclusion chromatography (SEC) to determine the molecular weight and oligomeric state of the protein

References:

1. D. Della Sala, et al. "FTIR spectroscopy combined with isotope labeling and DFT calculations for protein structure determination." Journal of Physical Chemistry B 117.41 (2013): 12609-12620.

2. C. Fritzsching, et al. "Combining FTIR spectroscopy and X-ray crystallography to study protein structure and function." Progress in Biophysics and Molecular Biology 119.1 (2015): 119-127.

3. M. Takeuchi, et al. "Protein structure determination using FTIR spectroscopy: combination with other biophysical methods." Analytical and Bioanalytical Chemistry 409.16 (2017): 3973-3983.

When characterizing proteins, combining FTIR with other analytical techniques enhances the understanding of their structure and properties. Recommended complementary analyses include Circular Dichroism (CD) spectroscopy, X-ray crystallography, Mass Spectrometry (MS), Nuclear Magnetic Resonance (NMR) spectroscopy, and Gel Electrophoresis. CD spectroscopy provides insights into protein secondary structure, X-ray crystallography determines atomic structure, MS identifies molecular weight and modifications, NMR reveals atomic-level details, and Gel Electrophoresis aids in determining protein purity and molecular weight. Integrating these techniques with FTIR provides a comprehensive understanding of protein structure, dynamics, and interactions, enabling researchers to uncover vital information about protein behavior and potential applications.