DNAα聚合酶对多核苷酸的识别
Polynucleotide recognition by DNA alpha-polymerase.
作者信息
Wilson S H, Matsukage A, Bohn E W, Chen Y C, Sivarajan M
出版信息
Nucleic Acids Res. 1977 Nov;4(11):3981-96. doi: 10.1093/nar/4.11.3981.
In a survey of template-primer preference of a mouse myeloma DNA alpha-polymerase, the fastest rate of DNA synthesis was with poly(dT) as template and (rA)24 as primer. Such a preference for poly(dT).oligo(rA) was not observed with other DNA polymerases of mouse origin. DNA synthesis in this system resulted in formation of oligo(dA) chains, not template-length poly(dA); thus, the average enzyme molecule bound to a poly(dT).(rA)24 complex and initiated a new oligo(dA) chain many times during the incubation. Binding experiments revealed that the alpha-polymerase had high affinity for poly(dT). Although the alpha-polymerase did not bind to poly(dl) and failed to replicate it inreactions with a base pair complementary primer, poly(dl) was replicated after a (dT) block had been grafted to its 3'-end and the oligo(rA) primer had been added. In similar experiments, the (dT) block was found to be much more effective than other 3'-terminal blocks in promoting replication of denatured calf thymus DNA. The results indicate that specific base sequences may regulate initiation of DNA syntehsis by this alpha-polymerase.
在一项关于小鼠骨髓瘤DNAα-聚合酶模板-引物偏好性的调查中，以聚（dT）为模板、（rA）24为引物时DNA合成速率最快。在源自小鼠的其他DNA聚合酶中未观察到对聚（dT）.寡聚（rA）的这种偏好。该系统中的DNA合成导致形成寡聚（dA）链，而非模板长度的聚（dA）；因此，在孵育过程中，平均每个酶分子会多次结合到聚（dT）.（rA）24复合物上并起始一条新的寡聚（dA）链。结合实验表明，α-聚合酶对聚（dT）具有高亲和力。尽管α-聚合酶不与聚（dl）结合，且在与碱基对互补引物的反应中无法复制它，但在其3'-末端接上（dT）块并添加寡聚（rA）引物后，聚（dl）得以复制。在类似实验中，发现（dT）块在促进变性小牛胸腺DNA的复制方面比其他3'-末端块有效得多。结果表明，特定的碱基序列可能调节这种α-聚合酶引发的DNA合成。
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