Chemical Laboratory, CSIR-Central Leather Research Institute , Adyar, Chennai 600020, India.
J Phys Chem B. 2018 Jan 25;122(3):1145-1151. doi: 10.1021/acs.jpcb.7b10645. Epub 2018 Jan 10.
Given the potential of productive interaction between choline-based amino acid ionic liquids (CAAILs) and collagen, we investigated the role of four CAAILs, viz., choline serinate, threoninate, lysinate, and phenylalaninate, and the changes mediated by them in the structure of collagen at different hierarchical orderings, that is, at molecular and fibrillar levels. The rheological, dielectric behavior and the secondary structural changes signify the alteration in the triple helical structure of collagen at higher concentrations of CAAILs. A marginal swelling and slight decrease in the thermal stability of rat tail tendon collagen fibers were observed for choline serinate and threoninate, albeit distortions in banding patterns were noticed for choline lysinate and phenylalaninate, suggesting chaotropicity of the ions at the fibrillar level. This signifies the changes in the hydrogen-bonding environment of collagen with increasing concentrations of CAAILs, which could be due to competitive hydrogen bonding between the carbonyl group of amino acid ionic liquids and the hydroxyl groups of collagen.
鉴于胆碱基氨基酸离子液体 (CAAIL) 与胶原蛋白之间具有潜在的生产交互作用，我们研究了四种 CAAIL，即丝氨酸胆碱、苏氨酸胆碱、赖氨酸胆碱和苯丙氨酸胆碱，以及它们在不同层次的结构变化中（即分子水平和纤维水平）介导的胶原蛋白变化。流变学、介电行为和二级结构的变化表明，在 CAAIL 较高浓度下，胶原蛋白的三螺旋结构发生了改变。尽管对赖氨酸胆碱和苯丙氨酸胆碱观察到带状图案的扭曲，但丝氨酸胆碱和苏氨酸胆碱对大鼠尾腱胶原纤维的轻微肿胀和热稳定性略有下降，这表明离子在纤维水平上具有亲液性。这表明随着 CAAIL 浓度的增加，胶原蛋白的氢键环境发生了变化，这可能是由于氨基酸离子液体的羰基与胶原蛋白的羟基之间存在竞争氢键。
