Samanta Nirnay, Mahanta Debasish Das, Mitra Rajib Kumar
Department of Chemical, Biological and Macromolecular Sciences, S.N. Bose National Centre for Basic Sciences, Block JD, Sector III, Salt Lake, Kolkata 700098, India.
Phys Chem Chem Phys. 2014 Nov 14;16(42):23308-15. doi: 10.1039/c4cp03273j.
The remarkable ability of guanidinium chloride (GdmCl) to denature proteins is a well studied yet controversial phenomenon; the exact molecular mechanism is still debatable, especially the role of hydration dynamics, which has been paid less attention. In the present contribution, we have addressed the issue of whether the collective hydrogen bond dynamics of water gets perturbed in the presence of GdmCl and its possible impact on the denaturation of a globular protein human serum albumin (HSA), using terahertz (THz) time domain spectroscopy (TTDS) in the frequency range of 0.3-2.0 THz. The collective hydrogen bond dynamics is determined by fitting the obtained complex dielectric response in a multiple Debye relaxation model. To compare the results, the studies were extended to two more salts: tetramethylguanidinium chloride (TMGdmCl) and sodium chloride (NaCl). It was concluded that the change in hydration dynamics plays a definite role in the protein denaturation process.
氯化胍（GdmCl）使蛋白质变性的显著能力是一个经过充分研究但仍存在争议的现象；确切的分子机制仍有争议，尤其是水合动力学的作用，这一点较少受到关注。在本论文中，我们使用太赫兹（THz）时域光谱（TTDS）在0.3 - 2.0 THz频率范围内，研究了在GdmCl存在的情况下，水的集体氢键动力学是否受到扰动及其对球状蛋白人血清白蛋白（HSA）变性的可能影响。通过在多重德拜弛豫模型中拟合所获得的复介电响应来确定集体氢键动力学。为了比较结果，研究扩展到另外两种盐：四甲基氯化铵（TMGdmCl）和氯化钠（NaCl）。得出的结论是，水合动力学的变化在蛋白质变性过程中起了一定作用。
