Enhanced activity of adenine-DNA glycosylase (Myh) by apurinic/apyrimidinic endonuclease (Ape1) in mammalian base excision repair of an A/GO mismatch
Enhanced activity of adenine-DNA glycosylase (Myh) by apurinic/apyrimidinic endonuclease (Ape1) in mammalian base excision repair of an A/GO mismatch
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DOI：
10.1093/nar/29.3.743
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发表时间：
2001-02-01
影响因子：
14.9
通讯作者：
Miller, JH
中科院分区：
文献类型：
--
作者：
Yang, HJ;Clendenin, WM;Miller, JH
大肠埃希菌的腺嘌呤-DNA糖基酶MutY与氧化损伤的碱基7，8-二氢-8-氧鸟嘌呤(GO)错配时，催化腺嘌呤的裂解。生物学结果是预防C/G-->；A/T转换。哺乳动物A/GO的碱基切除修复(BER)的分子机制尚不清楚。在这项研究中，我们报道了利用小鼠MutY同源物(MyH)和人AP内切酶(APE1)来刺激哺乳动物腺嘌呤-DNA糖基化酶活性的方法，该酶与小鼠同源物Apex有94%的氨基酸同源性。在Myh糖基酶活性去除腺嘌呤后，由于缺乏有效的Myh AP裂解酶活性，完整的AP DNA仍然存在。对野生型APE1及其催化突变体H309N的研究表明，APE1的催化活性是形成切割的AP DNA所必需的。APE1似乎还通过增加Myh-DNA复合体的形成来刺激Myh糖基酶的活性。这种刺激不依赖于APE1的催化活性，因此，APE1保留了MyH对A/GO的偏好而不是A/G，并提高了糖基酶的整体效率。我们的研究表明，在体内可能发生蛋白质-蛋白质相互作用，以实现A/GO的有效误码率。
Adenine-DNA glycosylase MutY of Escherichia coli catalyzes the cleavage of adenine when mismatched with 7,8-dihydro-8-oxoguanine (GO), an oxidatively damaged base. The biological outcome is the prevention of C/G-->A/T transversions. The molecular mechanism of base excision repair (BER) of A/GO in mammals is not well understood. In this study we report stimulation of mammalian adenine-DNA glycosylase activity by apurinic/apyrimidinic (AP) endonuclease using murine homolog of MutY (Myh) and human AP endonuclease (Ape1), which shares 94% amino acid identity with its murine homolog Apex. After removal of adenine by the Myh glycosylase activity, intact AP DNA remains due to lack of an efficient Myh AP lyase activity. The study of wild-type Ape1 and its catalytic mutant H309N demonstrates that Ape1 catalytic activity is required for formation of cleaved AP DNA. It also appears that Ape1 stimulates Myh glycosylase activity by increasing formation of the Myh-DNA complex. This stimulation is independent of the catalytic activity of Ape1, Consequently, Ape1 preserves the Myh preference for A/GO over A/G and improves overall glycosylase efficiency. Our study suggests that protein-protein interactions may occur in vivo to achieve efficient BER of A/GO.