Helix formation in model peptides based on nucleolin TPAKK motifs.
Helix formation in model peptides based on nucleolin TPAKK motifs.
复制标题
基于核仁素 TPAKK 基序的模型肽中的螺旋形成。
DOI：
10.1002/bip.360350110
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发表时间：
1995
期刊：
影响因子：
2.9
通讯作者：
Nelson,JW
中科院分区：
文献类型：
--
作者：
Xu,X;Cooper,LG;DiMario,PJ;Nelson,JW
通过 CD 和 nmr 研究了核仁蛋白 nucleolin N 端结构域的肽模型形成的结构。肽的序列基于推定的核酸结合序列基序TPAKK：肽TP1和TP2具有序列乙酰基-G(ATPAKKAA)nG-酰胺，其中n分别=1和2。 CD 测量表明，当赖氨酸侧链不带电荷时，通过增加 pH 值或侧链胺的乙酰化，两种肽的结构发生变化。当添加三氟乙醇 (TFE) 时，会观察到更广泛的结构变化，类似于基于核磁共振核欧沃豪瑟效应 (NOE) 和 Cα 质子化学位移变化以及圆二色光谱的螺旋结构。核磁共振观察到，在 0.5M NaClO4 中形成的结构与赖氨酸侧链乙酰化时形成的结构相似，这可能是由于高氯酸根离子与赖氨酸侧链电荷的相互作用所致。 TPAKK 基序中观察到的螺旋结构可能通过涉及苏氨酸的 N 封端相互作用来稳定。 TFE 中观察到的结构表明，Thr-Pro 序列启动了 TPAKK 基序中的短螺旋片段，这些螺旋结构可能与核酸相互作用，大概是通过核仁素的赖氨酸和苏氨酸之间的相互作用。 © 1995 约翰威利父子公司。
The structures formed by peptide models of the N‐terminal domain of the nucleolar protein nucleolin were studied by CD and nmr. The sequences of the peptides are based on the putative nucleic acid binding sequence motif TPAKK: The peptides TP1 and TP2 have the sequence acetyl‐G(ATPAKKAA)nG‐amide, withn= 1 and 2, respectively. CD measurements indicate structural changes in both peptides when the lysine side chains are uncharged by increasing the pH or acetylation of the side‐chain amines. When trifluoroethanol (TFE) is added, more extensive structural changes are observed, resembling helical structure based on nmr nuclear Overhauser effect (NOE) and Cαproton chemical shift changes, and CD spectra. The structure formed in 0.5M NaClO4as observed by nmr is similar to that when the lysine side chains are acetylated, due presumably to interactions of perchlorate ion with side‐chain charges on lysines. The helical structure observed in TPAKK motifs may be stabilized via N‐capping interactions involving threonine. The structures observed in TFE suggest that the Thr‐Pro sequence initiates short helical segments in TPAKK motifs, and these helical structures might interact with nucleic acids, presumably via interactions between lysines and threonines of nucleolin. © 1995 John Wiley & Sons, Inc.