Faculty of Biology, Chemistry and Pharmacy, Institute of Pharmacy/Institute of Chemistry and Biochemistry, Freie Universität Berlin, Königin-Luise-Strasse 2+4, 14195 Berlin (Germany); Department of Medicinal Chemistry/Chemical Biology, Leibniz-Institut für Molekulare Pharmakologie, Robert-Rössle-Strasse 10, 13125 Berlin (Germany); Current address: Fraunhofer Institute for Manufacturing Technology and Advanced Materials (IFAM), Adhesive Bonding Technology and Surfaces, Wiener Strasse 12, 28359 Bremen (Germany).
Chembiochem. 2013 Oct 11;14(15):1982-90. doi: 10.1002/cbic.201300365. Epub 2013 Sep 24.
Copolymers of N-(2-hydroxypropyl)methacrylamide (HPMA) and N-methacryloyl-β-alaninyl-S-benzyl thioester were prepared by employing free radical or RAFT conditions and denominated as "NCL polymers". The copolymer with a polydispersity index of 1.2-1.3 was used for the direct conjugation of unprotected peptides and peptide mixtures bearing differentially loaded side chains by native chemical ligation reactions conducted in aqueous buffer. Uptake into human HeLa cells was correlated with the overall surface charge and the ζ potentials of the peptide-polymer conjugates. Most notable were the differential effects found for various multivalent peptide-polymer conjugates containing arginine residues. Although positive ζ potentials were required for cellular uptake of the peptide-polymer conjugates, this sole charge effect was strongly dominated by the effect exerted by the relative distribution of arginine residues. Polymers conjugated with nona-arginine peptides were over-proportionally taken up, relative to their surface charge, compared to polymers with random distribution of single arginine residues. In view of these findings, peptide-polymer compositions suitable for efficient cellular uptake with negligible toxicity at polymer concentrations relevant for intracellular functional studies were determined.
N-（2-羟丙基）甲基丙烯酰胺（HPMA）与 N-甲基丙烯酰基-β-丙氨酰基-S-苄硫酯的共聚物是通过自由基或 RAFT 条件制备的，并被称为“NCL 聚合物”。该共聚物的分散指数为 1.2-1.3，用于通过在水性缓冲液中进行的天然化学连接反应直接连接未保护的肽和带有差异负载侧链的肽混合物。肽-聚合物缀合物的整体表面电荷和 ζ 电位与人类 HeLa 细胞的摄取有关。最值得注意的是，对于含有精氨酸残基的各种多价肽-聚合物缀合物，发现了不同的影响。尽管肽-聚合物缀合物的细胞摄取需要正 ζ 电位，但这种单一电荷效应主要受到精氨酸残基相对分布的影响。与随机分布单个精氨酸残基的聚合物相比，与非精氨酸肽缀合的聚合物的摄取量不成比例地增加，相对于其表面电荷而言。鉴于这些发现，确定了适合于在与细胞内功能研究相关的聚合物浓度下具有可忽略毒性的有效细胞摄取的肽-聚合物组合物。
