An effective and facile synthesis of six novel tetraphosphate cap analogs modified with a methylenebis(phosphonate) moiety (1â6) is presented. Analogs have been rationally designed to bind tightly to the eukaryotic initiation factor 4E (eIF4E) responsible for cap binding during the initiation of translation, and have increased stability owing to resistance to enzymatic degradation. Final compounds turned out to have significantly higher association constant values (KAS) for binding to eIF4E (5â9 fold higher than standard). Four of the analogs were resistant towards enzymatic degradation by human Decapping Scavenger enzyme (DcpS). Binding studies of non-hydrolyzable analogs with DcpS revealed a broad range of KAS values for different analogs. All of the analogs were potent inhibitors of translation in a rabbit reticulocyte lysate system (RRL) and those resistant to DcpS turned out to be stable under an elongated time of preincubation while the inhibitory potency of standard was diminished in these conditions. For Anti Reverse Cap Analog (ARCA) dinucleotides (4â6), we have shown that they are effectively incorporated into mRNA and transcripts capped with these analogs undergo translation in vitro.
本文介绍了一种有效而简便的合成方法,即用亚甲基双(
膦酸盐)分子修饰六种新型
四磷酸帽类似物(1â6)。这些类似物经过合理设计,能与真核
生物起始因子 4E(eIF4E)紧密结合,该因子在翻译起始过程中负责帽的结合,并且由于耐酶降解而具有更高的稳定性。最终化合物与 eIF4E 的结合常数(KAS)明显更高(比标准值高 5â9 倍)。其中四种类似物对人类解旋清道夫酶(DcpS)的酶降解具有抗性。非
水解类似物与 DcpS 的结合研究显示,不同类似物的 KAS 值范围很广。在兔网状细胞裂解物系统(RRL)中,所有类似物都是有效的翻译
抑制剂,而且对 DcpS 具有抗性的类似物在延长预孵育时间后变得稳定,而标准类似物的抑制效力则在这些条件下减弱。对于抗逆转录酶帽类似物(ARCA)二核苷酸(4â6),我们已经证明它们能有效地结合到 mRNA 中,并且用这些类似物封端的转录本会在体外进行翻译。