Department of Physical Chemistry, Gdańsk University of Technology, Narutowicza 11/12, 80-233 Gdańsk, Poland.
Department of Inorganic Chemistry, Gdańsk University of Technology, Narutowicza 11/12, 80-233 Gdańsk, Poland.
Int J Mol Sci. 2022 Feb 7;23(3):1872. doi: 10.3390/ijms23031872.
Interactions between a solvent and their co-solute molecules in solutions of peptides are crucial for their stability and structure. The K-peptide is a synthetic fragment of a larger hen egg white lysozyme protein that is believed to be able to aggregate into amyloid structures. In this study, a complex experimental and theoretical approach is applied to study systems comprising the peptide, water, and two co-solutes: trimethylamide -oxide (TMAO) or dimethyl sulfoxide (DMSO). Information about their interactions in solutions and on the stability of the K-peptide was obtained by FTIR spectroscopy and differential scanning microcalorimetry. The IR spectra of various osmolyte-water-model-peptide complexes were simulated with the DFT method (B3LYP/6-311++G(d,p)). The FTIR results indicate that both solutes are neutral for the K-peptide in solution. Both co-solutes affect the peptide to different degrees, as seen in the shape of its amide I band, and have different influences on its thermal stability. DFT calculations helped simplify the experimental data for easier interpretation.
溶剂与其共溶质分子在肽溶液中的相互作用对其稳定性和结构至关重要。K 肽是一种较大的鸡卵清溶菌酶蛋白质的合成片段，据信能够聚集形成淀粉样结构。在这项研究中，应用了一种复杂的实验和理论方法来研究包含肽、水和两种共溶质的系统：三甲基氧化胺（TMAO）或二甲亚砜（DMSO）。通过傅里叶变换红外光谱和差示扫描量热法获得了有关它们在溶液中的相互作用以及 K 肽稳定性的信息。用 DFT 方法（B3LYP/6-311++G（d，p））模拟了各种渗透剂-水-模型肽复合物的红外光谱。FTIR 结果表明，两种溶质在溶液中对 K 肽均呈中性。两种共溶质对肽的影响程度不同，如酰胺 I 带的形状所示，并且对其热稳定性有不同的影响。DFT 计算有助于简化实验数据以方便解释。
