Key interactions with deazariboflavin cofactor for light-driven energy transfer in Xenopus (6-4) photolyase
Key interactions with deazariboflavin cofactor for light-driven energy transfer in Xenopus (6-4) photolyase
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DOI：
10.1007/s43630-021-00065-3
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发表时间：
2021-06-13
影响因子：
3.1
通讯作者：
Yamamoto, Junpei
中科院分区：
文献类型：
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作者：
Morimoto, Ayaka;Hosokawa, Yuhei;Yamamoto, Junpei
光解酶是一种黄酮类酶，负责在紫外线照射下对DNA中形成的致癌交联进行光驱动修复。它们具有两个非共价结合的发色团：黄素腺嘌呤二核苷酸（FAD）作为催化中心和辅助天线发色团，用于收集光子并将太阳能传递到催化中心。虽然能量转移反应已经被时间分辨光谱表征，但了解自然生物系统如何很好地组织发色团进行有效的能量转移是非常重要的。在这里，我们全面表征了8-羟基-7,8-二甲基-5-去氮杂黄素（8-HDF）与爪蟾（6-4）光解酶的结合。硅模拟表明，位于结合位点入口的疏水氨基酸残基在8-HDF结合时主导环的易位，该残基的突变导致DNA修复反应中有效能量转移功能障碍。对该蛋白的突变分析和对发色团的修饰表明，该蛋白中带正电的残基与8-HDF中的苯氧基之间的库仑相互作用对8-HDF的定向调节起着关键作用。本研究为爪蟾（6-4）光解酶可以利用8-HDF作为光收集发色团提供了明确的证据。对天然天线分子结合的新认识将有助于人工捕光发色团的开发和（6-4）光解酶能量传递的光谱学研究。
Photolyases are flavoenzymes responsible for light-driven repair of carcinogenic crosslinks formed in DNA by UV exposure. They possess two non-covalently bound chromophores: flavin adenine dinucleotide (FAD) as a catalytic center and an auxiliary antenna chromophore that harvests photons and transfers solar energy to the catalytic center. Although the energy transfer reaction has been characterized by time-resolved spectroscopy, it is strikingly important to understand how well natural biological systems organize the chromophores for the efficient energy transfer. Here, we comprehensively characterized the binding of 8-hydroxy-7,8-didemethyl-5-deazariboflavin (8-HDF) to Xenopus (6-4) photolyase. In silico simulations indicated that a hydrophobic amino acid residue located at the entrance of the binding site dominates translocation of a loop upon binding of 8-HDF, and a mutation of this residue caused dysfunction of the efficient energy transfer in the DNA repair reaction. Mutational analyses of the protein combined with modification of the chromophore suggested that Coulombic interactions between positively charged residues in the protein and the phenoxide moiety in 8-HDF play a key role in accommodation of 8-HDF in the proper direction. This study provides a clear evidence that Xenopus (6-4) photolyase can utilize 8-HDF as the light-harvesting chromophore. The obtained new insights into binding of the natural antenna molecule will be helpful for the development of artificial light-harvesting chromophores and future characterization of the energy transfer in (6-4) photolyase by spectroscopic studies.