Luijten Jeroen, Vorenkamp Eltjo J, Schouten Arend J
Department of Polymer Chemistry, University of Groningen, Nijenborgh 4, 9747 AG Groningen, The Netherlands.
Langmuir. 2007 Oct 9;23(21):10772-8. doi: 10.1021/la7011217. Epub 2007 Sep 15.
The reversible manipulation of the helix screw sense in surface-grafted poly(beta-phenethyl-L-aspartate) (PPELA) films by means of external stimuli was investigated. Ringopening polymerization of beta-phenethyl-L-aspartate N-carboxyanhydride initiated from primary amino-functionalized silicon and quartz substrates results in surface-grafted PPELA films in which the end-grafted polypeptide chains have a right-handed alpha-helical conformation. Upon annealing of the film at 150 degrees C for 30 min, a helix screw sense inversion takes place and the grafted chains adopt a left-handed pi-helical conformation. In the solid state, this left-handed pi-helical form is completely stable and cannot be changed by reheating and/or cooling. Upon immersion of the annealed grafted film in chloroform or other helicogenic solvents, the grafted polypeptide chains completely revert to their original right-handed alpha-helical form. Successive annealing and solvent treatment steps show that this helix sense inversion cycle can be repeated many times.
研究了通过外部刺激对表面接枝聚（β-苯乙-L-天冬氨酸）（PPELA）薄膜中螺旋方向的可逆操纵。由伯氨基官能化的硅和石英基底引发的β-苯乙-L-天冬氨酸N-羧基酐的开环聚合反应会形成表面接枝的PPELA薄膜，其中末端接枝的多肽链具有右手α-螺旋构象。将薄膜在150℃退火30分钟后，螺旋方向发生反转，接枝链呈现左手π-螺旋构象。在固态下，这种左手π-螺旋形式完全稳定，不会因重新加热和/或冷却而改变。将退火后的接枝薄膜浸入氯仿或其他致螺旋溶剂中时，接枝的多肽链会完全恢复到其原始的右手α-螺旋形式。连续的退火和溶剂处理步骤表明，这种螺旋方向反转循环可以重复多次。
