Alkyltransferase-like protein clusters scan DNA rapidly over long distances and recruit NER to alkyl-DNA lesions
Alkyltransferase-like protein clusters scan DNA rapidly over long distances and recruit NER to alkyl-DNA lesions
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DOI：
10.1073/pnas.1916860117
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发表时间：
2020-04
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影响因子：
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通讯作者：
Natascha Rill;Ann Mukhortava;S. Lorenz;I. Tessmer
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作者：
Natascha Rill;Ann Mukhortava;S. Lorenz;I. Tessmer
我们通过烷基转移酶样蛋白（ATL）和原核核苷酸切除修复（NER）启动酶UvrA直接观察DNA上的共易位。我们的研究结果增强了对外源性肾内瘤病灶再募集的理解。此外，我们还阐明了ATL及其催化活性同源物AGT的DNA损伤搜索和识别机制。我们的数据支持了从ATL（和AGT）的低聚损伤搜索复合物到基于低聚结构解离的修复启动的单体蛋白复合物的过渡范式，这是由于在目标病变处稳定，更强的DNA弯曲。DNA中鸟嘌呤碱基的烷基化由于其高诱变和细胞毒性而对细胞有害，并通过烷基转移酶AGT进行修复。此外，在许多生物体中发现了与agt结构相似的烷基转移酶样蛋白（ATLs）。虽然atl本身不具有催化活性，但强有力的证据表明，atl靶向核苷酸切除修复系统（NER）的烷基损伤。利用单分子和集合方法的结合，我们在这里展示了ATL将原核生物NER的起始酶UvrA招募到烷基损伤上。我们进一步描述了ATL对病变的识别，并在分子水平上通过高运动性ATL和ATL - uvra复合物在DNA上直接可视化DNA病变搜索。基于ATL和AGT的dna相互作用域的高度相似性，我们的研究结果为ATL和AGT的病变搜索机制提供了重要的见解，从而为在化疗期间控制AGT的作用以获得治疗效益开辟了机会。
Significance We directly visualize cotranslocation on DNA by the alkyltransferase-like protein, ATL, and UvrA, the initiating enzyme of prokaryotic nucleotide excision repair (NER). Our findings offer an enhanced understanding of the recruitment of NER to nonnative NER target lesions. Furthermore, we elucidate the mechanism of DNA lesion search and recognition by ATL and its catalytically active homolog AGT. Our data support a paradigm for the transition from oligomeric lesion search complexes of ATL (and AGT) to the repair-initiating, monomeric protein complexes based on the dissociation of oligomeric structures due to stable, stronger DNA bending at a target lesion. Alkylation of guanine bases in DNA is detrimental to cells due to its high mutagenic and cytotoxic potential and is repaired by the alkyltransferase AGT. Additionally, alkyltransferase-like proteins (ATLs), which are structurally similar to AGTs, have been identified in many organisms. While ATLs are per se catalytically inactive, strong evidence has suggested that ATLs target alkyl lesions to the nucleotide excision repair system (NER). Using a combination of single-molecule and ensemble approaches, we show here recruitment of UvrA, the initiating enzyme of prokaryotic NER, to an alkyl lesion by ATL. We further characterize lesion recognition by ATL and directly visualize DNA lesion search by highly motile ATL and ATL–UvrA complexes on DNA at the molecular level. Based on the high similarity of ATLs and the DNA-interacting domain of AGTs, our results provide important insight in the lesion search mechanism, not only by ATL but also by AGT, thus opening opportunities for controlling the action of AGT for therapeutic benefit during chemotherapy.