Gitsas A, Floudas G, Mondeshki M, Butt H-J, Spiess H W, Iatrou H, Hadjichristidis N
Department of Physics, University of Ioannina, Post Office Box 1186, 45110 Ioannina, Greece.
Biomacromolecules. 2008 Jul;9(7):1959-66. doi: 10.1021/bm800221n. Epub 2008 Jun 20.
The effect of chain topology on (i) the peptide secondary structure, (ii) the nanophase self-assembly, and (iii) the local segmental and global peptide relaxations has been studied in a series of model diblock and 3-arm star copolypeptides of poly(epsilon-carbobenzyloxy-L-lysine) (PZLL) and poly(gamma-benzyl-L-glutamate) (PBLG) with PZLL forming the core. Diblock copolypeptides are nanophase separated with PBLG and PZLL domains comprising alpha-helices packed in a hexagonal lattice. Star copolypeptides are only weakly phase separated, comprising PBLG and PZLL alpha-helices in a pseudohexagonal lattice. Phase mixing has profound consequences on the local and global dynamics. The relaxation of the peptide secondary structure speeds up, and the helix persistence length is further reduced in the stars, signifying an increased concentration of helical defects.
在一系列以聚（ε-苄氧羰基-L-赖氨酸）（PZLL）为核心、聚（γ-苄基-L-谷氨酸）（PBLG）为组成部分的模型二嵌段和三臂星形共多肽中，研究了链拓扑结构对（i）肽二级结构、（ii）纳米相自组装以及（iii）局部链段和整体肽弛豫的影响。二嵌段共多肽发生纳米相分离，PBLG和PZLL结构域包含以六方晶格堆积的α-螺旋。星形共多肽仅发生弱相分离，在准六方晶格中包含PBLG和PZLLα-螺旋。相混合对局部和整体动力学有深远影响。肽二级结构的弛豫加快，并且在星形结构中螺旋持续长度进一步减小，这表明螺旋缺陷的浓度增加。
