A decanucleotide dC-C-C-T-C-G-A-G-G-G was synthesized by phosphotriester block condensation. Three protected blocks, dCCCTp, dCGAp and dGGG were prepared using N-acyl, 5'-O-monomethoxytrityldeoxynucleosides as the starting materials. The protected dGGG which served as the 3'-terminal block was synthesized by condensation of 3'-O-benzoyl-N-isobutyryldeoxyguanosine (5'-hydroxy component) with 5'-O-monomethoxytrityl-N-isobutyryldeoxyguanosine 3'-O-p-chlorophenyl phosphate (3'-O-phosphodie ster component) using mesitylenesulfonyl triazolide as the condensing reagent followed by removal of the 5'-monomethoxytrityl group for repeated condensation. The other two blocks were prepared by using the 3'-O-p-chlorophenyl phosphoranilidate of N, 5'-protected deoxynucleosides as the 3'-end unit (5'-hydroxy component). The phosphoranilidate of the fully protected trimers was removed by treatment with isoamyl nitrite for the condensation with the 5'-hydroxyl group of the growing chain. Fully protected nucleotides were isolated by chromatography on silica gel and the deblocked product was purified by ionexchange chromatography on DEAE-cellulose. The decanucleotide was characterized by mobility shift analysis and complete enzymatic digestions after labelling the 5'-end with [γ-32P] ATP using polynucleotide kinase.
通过
磷酸酯块缩合合成了十核苷酸 dC-C-C-T-C-G-A-G-G-G。以 N-酰基、5'-O-单甲氧基三苯甲基脱氧核苷酸为起始原料,制备了三个受保护的嵌段:dCCCTp、dCGAp 和 dGGG。作为 3'- 末端嵌段的受保护 dGGG 是通过 3'-O- 苯甲酰基-N-异丁酰基脱氧
鸟苷(5'-羟基成分)与 5'-O- 单甲氧基三苯甲基-N-异丁酰基脱氧
鸟苷 3'- O- 对
氯苯基
磷酸酯(5'-羟基成分)缩合合成的。O-对
氯苯基
磷酸酯(3'-O-
磷酸酯成分),使用甲磺酰三唑烷作为缩合试剂,然后去除 5'-monomethoxytrityl 基团进行重复缩合。另外两个区块是以 N,5'-受保护的脱氧核苷的 3'-O-对
氯苯基膦酰
苯胺为 3'-末端单元(5'-羟基成分)制备的。用
亚硝酸异戊酯处理完全保护的三聚体,使其与生长链的 5'-羟基缩合,从而除去完全保护的三聚体的
磷酰苯胺。通过
硅胶色谱法分离出完全保护的核苷酸,并通过
DEAE-
纤维素离子交换色谱法纯化脱锁产物。在使用多核苷酸激酶用[γ-32P]
ATP 标记 5'-end 后,十核苷酸的特征通过迁移分析和完全酶解来确定。