Arunkumar A I, Kumar T K, Sivaraman T, Yu C
Department of Chemistry, National Tsing Hua University, Hsinchu, Taiwan.
Int J Biol Macromol. 1997 Dec;21(4):299-305. doi: 10.1016/s0141-8130(97)00065-2.
The effect of acetonitrile on the random coil, alpha-helix and beta-sheet conformations induced in poly-L-lysine is studied. It is found that acetonitrile at higher concentrations transforms the backbone of polylysine from a random coil to a helical conformation. Addition of acetonitrile to polylysine (pH 11.5) in the alpha-helix conformation, induces conformational changes in two stages. At concentrations below 60% v/v, acetonitrile stabilizes the helical conformation and at higher concentrations (> 70% v/v), it destabilizes the helix. beta-sheet-->alpha-helix-->random coil conformational transitions are found to occur when polylysine in the heat-induced conformation is titrated with acetonitrile. The possible mechanism(s) of action of acetonitrile in inducing these structural transitions is discussed.
研究了乙腈对聚-L-赖氨酸中诱导产生的无规卷曲、α-螺旋和β-折叠构象的影响。发现较高浓度的乙腈会使聚赖氨酸的主链从无规卷曲转变为螺旋构象。向处于α-螺旋构象的聚赖氨酸（pH 11.5）中添加乙腈，会分两个阶段诱导构象变化。在浓度低于60% v/v时，乙腈使螺旋构象稳定，而在较高浓度（> 70% v/v）时，它会使螺旋不稳定。当用乙腈滴定热诱导构象的聚赖氨酸时，发现会发生β-折叠→α-螺旋→无规卷曲的构象转变。讨论了乙腈诱导这些结构转变的可能作用机制。
