Fourier transform infrared spectroscopy protein-surface studies

Fourier Transform Infrared Spectroscopy for Protein—Surface Studies... 

Leufgen et al. [82] reported the investigation of a template-assembled synthetic protein (TASP) conformation and its orientation in self-assembled monolayers (SAM) by means of TOF-SIMS. In this study, both the presence and molecular orientation of the TASP molecule can be monitored by TOF-SIMS, and furthermore, the influence of self-assembly protocols on the TASP molecular surface orientation can be studied by TOF-SIMS, although Fourier transform infrared spectroscopy (FTIR) and surface plasmon resonance (SPR) fail in this case. 

In early work (8) we used infrared spectroscopy coupled with attenuated total reflection optics. This work was done before the availability of infrared equipment based on Fourier transform methods. Due to their relative speed these methods now permit in situ, real time measurements with a resolution of 1 sec or less (9), and continue to yield valuable data, particularly in the hands of the Battelle group in a series of studies dating from 1979 (10). In our early infrared work we had to be content to rinse and dry the surface before obtaining the infrared reflection spectrum Nevertheless the values of surface concentration were remarkably close to those determined more recently. Infrared studies of proteins suffer generally from the fact that the main features of protein spectra are similar for all proteins and therefore it is difficult to distinguish one from another. 

The combination of infrared reflection absorption spectroscopy and the Fourier transform technique has proven to be useful for structural studies of mono-molecular protein and amino acid films formed on metal surfaces. All protein films investigated exhibit a distinct blue shift of the Amide I frequency upon adsorption on metal surfaces, compared to the same band in aqueous solution. The magnitude of this blue shift seems to be larger for proteins with dominating )8-structure (32 cm" ) than for those with a large amount of a-helix or disordered structures (ca. 20 cm" ). It is concluded from reference spectra of... 

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