Center for Relativistic Laser Science

121st Summer Symposium of KCS-Physical Chemistry Division (2016)

Nowadays, variety of IR probes such as nitrile, azido, thiocyanato, selenocyanato groups and carbon monoxide is widely used to study protein structure, function and dynamics [1]. In our research two specific systems were studied using different IR probes.

Firstly, a new vibrational probe based on isonitrile (NC)-derivatized alanine (Ac-Ala(NC)-NHMe) was synthesized and its structure and vibrational dynamics of its NC stretch mode were examined utilizing FTIR and femtosecond IR pump−probe spectroscopy [2]. It has been found that the probe is characterized by very high sensivity to the hydrogen bonding environment, it possesses larger dipole strength when attached to the aliphatic group and its vibrational lifetime is several times longer than that of azido (N₃) stretch mode.

In the second project carbon monoxide was utilized to extract the information about the effect of the osmolytes on protein-water environment in the myoglobin-osmolytes system. Carbonmonoxide-myoglobin - osmolytes systems were studied using FTIR, UV-VIS, CD and IR pump-probe spectroscopy. Interestingly, a change in the lifetime of CO-myoglobin upon addition of the osmolytes (glycine betaine and sorbitol) was observed. In addition, the temperature-dependent CD studies revealed the different behavior of protein unfolding process in case of GB and sorbitol.

References

[1] Kim H. and Cho M. Infrared Probes for Studying the Structure and Dynamics of Biomolecules Chem. Rev. 2013. 113, pp 5817–5847,

[2] Maj M, Ahn C, Kossowska D, Park K, Kwak K, Han H, Cho M. β-Isocyanoalanine as an IR probe: comparison of vibrational dynamics between isonitrile and nitrile-derivatized IR probes. Phys. Chem. Chem. Phys. 2015. 17, 11770-11778.