Translocation of a β-peptide across cell membranes
Translocation of a β-peptide across cell membranes
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DOI：
10.1021/ja017283v
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发表时间：
2002-01-23
影响因子：
15
通讯作者：
Gellman, SH
中科院分区：
文献类型：
--
作者：
Umezawa, N;Gelman, MA;Gellman, SH
从DNA结合蛋白衍生的短阳离子肽（HIV达特是其中的原型）可以穿过活细胞的膜，并且它们可以将共价连接的部分（蛋白质、药物）沿着。我们表明，达特47-57的β-氨基酸类似物以与达特47-57本身相当的效率（YGRKKRRQRRR）进入HeLa细胞。β-肽由在β-碳上带有适当侧链的残基组成。α-和β-肽均在N末端与荧光素缀合，并通过共聚焦荧光显微镜监测细胞渗透。从α-肽中删除三个C-末端精氨酸残基消除了易位活性，与先前的报告一致，从β-肽中删除三个C-末端β3-高精氨酸残基具有类似的不良反应。因此，α-和β-肽易位过程显示出相似的长度/电荷依赖性。β-肽在水中似乎大部分未折叠，这与短Tat衍生的α-肽的行为一致，但在甲醇中β-肽采用螺旋构象，与短Tat衍生的α-肽相反。我们的研究结果表明，既不改变低聚骨架（酰胺基团间距），也不增加采用特定二级结构的内在倾向，影响易位活性。
Short cationic peptides derived from DNA-binding proteins, of which HIV Tat is a prototype, can cross the membranes of living cells, and they can bring covalently attached moieties (proteins, drugs) along with them. We show that a β-amino acid analogue of Tat 47-57 enters HeLa cells with comparable efficiency to Tat 47-57 itself (YGRKKRRQRRR). The β-peptide is comprised of residues that bear the appropriate side chain at the β-carbon. Both the α- and the β-peptide were conjugated to fluorescein at the N terminus, and cell penetration was monitored by confocal fluorescence microscopy. Deletion of the three C-terminal arginine residues from the α-peptide abolished translocation activity, consistent with prior reports, and deletion of the three C-terminal β3-homoarginine residues from the β-peptide had a similarly adverse effect. Thus, α- and β-peptide translocation processes show similar length/charge dependence. The β-peptide appeared to be largely unfolded in water, which is consistent with the behavior of short Tat-derived α-peptides, but in methanol the β-peptide adopted a helical conformation, in contrast to short Tat-derived α-peptides. Our results show that neither altering the oligomeric backbone (amide group spacing) nor increasing the intrinsic propensity to adopt a specific secondary structure affects translocation activity.