Burgers P M, Kornberg A
J Biol Chem. 1982 Oct 10;257(19):11468-73.
ATP (or dATP) stimulates DNA synthesis by DNA polymerase III holoenzyme (holoenzyme) on the synthetic template-primer poly(dA).oligo(dT)12. Nonhydrolyzable ATP analogs and other natural (deoxy)ribonucleoside triphosphates are inactive. Because the nonhydrolyzable analog 5'-deoxyadenylylimidodiphosphate is efficiently used by holoenzyme for incorporation, the ATP (or dATP) requirement for activation of replication of natural DNA could be determined. Analysis of lag times in DNA synthesis and isolation of intermediates showed that ATP (or dATP) is required in the formation of an initiation complex between holoenzyme and primed DNA template, but not for subsequent DNA synthesis. ATP is bound to holoenzyme in the absence of DNA with a KD value of 0.8 microM; 2 to 3 molecules of ATP per molecule of holoenzyme are bound without apparent cooperativity. Binding of ATP to DNA polymerase III (holoenzyme minus beta subunit) is weak (KD greater than 5 microM) and binding to the beta subunit alone is not observed. However, holoenzyme reconstituted by mixing DNA polymerase III with beta subunit binds ATP as tightly (KD = 0.6 microM) as the original holoenzyme.
ATP（或dATP）可刺激DNA聚合酶III全酶在合成模板引物聚（dA）·寡聚（dT）12上进行DNA合成。不可水解的ATP类似物和其他天然（脱氧）核糖核苷三磷酸无活性。由于不可水解类似物5'-脱氧腺苷酰亚氨基二磷酸能被全酶有效用于掺入，因此可以确定天然DNA复制激活所需的ATP（或dATP）。对DNA合成中延迟时间的分析以及中间体的分离表明，在全酶与引发的DNA模板之间形成起始复合物时需要ATP（或dATP），但后续DNA合成不需要。在没有DNA的情况下，ATP以0.8微摩尔的KD值与全酶结合；每分子全酶结合2到3个ATP分子，无明显协同性。ATP与DNA聚合酶III（不含β亚基的全酶）的结合较弱（KD大于5微摩尔），且未观察到其与单独的β亚基结合。然而，通过将DNA聚合酶III与β亚基混合重构的全酶与ATP的结合紧密程度（KD = 0.6微摩尔）与原始全酶相同。
