Lesion search and recognition by thymine DNA glycosylase revealed by single molecule imaging.
Lesion search and recognition by thymine DNA glycosylase revealed by single molecule imaging.
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DOI：
10.1093/nar/gkv139
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发表时间：
2015-03-11
影响因子：
14.9
通讯作者：
Tessmer I
中科院分区：
文献类型：
--
作者：
Buechner CN;Maiti A;Drohat AC;Tessmer I
DNA 糖基化酶能够快速有效地检测大量未受损 DNA 碱基中的损伤，这对于碱基切除修复 (BER) 至关重要。在这里，我们使用由 2-氨基嘌呤荧光碱基翻转测定支持的原子力显微镜 (AFM) 的单分子成像来研究人胸腺嘧啶 DNA 糖基化酶 (hTDG) 的损伤搜索，该酶启动 DNA 中诱变和细胞毒性 G:T 和 G:U 错配的 BER。我们的数据揭示了 hTDG-DNA 复合物的两种构象状态之间的平衡，指定为搜索复合物 (SC) 和询问复合物 (IC)，无论是在目标病变还是未受损的 DNA 位点。值得注意的是，对于 hTDG 和第二种糖基化酶 hOGG1（识别结构上不同的 8-氧代鸟嘌呤损伤）来说，SC 中 DNA 的构象反映了它们各自靶位点的先天结构特性。在 IC 中，DNA 急剧弯曲，如 hTDG 病变识别复合物的晶体结构所示，这可能支持病变识别所需的碱基翻转。我们的结果支持了将糖基化酶雕刻到其目标的潜在通用概念，使它们能够利用 DNA 弯曲的能量成本进行初始病变传感，并在 DNA 糖基化酶搜索病变期间进行连续（螺旋外）碱基询问。
The ability of DNA glycosylases to rapidly and efficiently detect lesions among a vast excess of nondamaged DNA bases is vitally important in base excision repair (BER). Here, we use single molecule imaging by atomic force microscopy (AFM) supported by a 2-aminopurine fluorescence base flipping assay to study damage search by human thymine DNA glycosylase (hTDG), which initiates BER of mutagenic and cytotoxic G:T and G:U mispairs in DNA. Our data reveal an equilibrium between two conformational states of hTDG–DNA complexes, assigned as search complex (SC) and interrogation complex (IC), both at target lesions and undamaged DNA sites. Notably, for both hTDG and a second glycosylase, hOGG1, which recognizes structurally different 8-oxoguanine lesions, the conformation of the DNA in the SC mirrors innate structural properties of their respective target sites. In the IC, the DNA is sharply bent, as seen in crystal structures of hTDG lesion recognition complexes, which likely supports the base flipping required for lesion identification. Our results support a potentially general concept of sculpting of glycosylases to their targets, allowing them to exploit the energetic cost of DNA bending for initial lesion sensing, coupled with continuous (extrahelical) base interrogation during lesion search by DNA glycosylases.
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影响因子：
4.8
作者：
Buechner, Claudia N.;Heil, Korbinian;Tessmer, Ingrid
通讯作者：
Tessmer, Ingrid
影响因子：
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作者：
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通讯作者：
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影响因子：
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作者：
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通讯作者：
O'Brien, Patrick J.
沿DNA糖基酶损伤搜索途径的复合物的静电特性。
影响因子：
2.9
作者：
Cravens, Shannen L.;Hobson, Matthew;Stivers, James T.
通讯作者：
Stivers, James T.
影响因子：
14.9
作者：
Hashimoto H;Hong S;Bhagwat AS;Zhang X;Cheng X
通讯作者：
Cheng X