The nuclease/helicase DNA2 plays important roles in DNA replication, repair and processing of stalled replication forks. DNA2 contains an iron-sulphur (FeS) cluster, conserved in eukaryotes and in a related bacterial nuclease. FeS clusters in DNA maintenance proteins are required for structural integrity and/or act as redox-sensors. Here, we demonstrate that loss of the FeS cluster affects binding of human DNA2 to specific DNA substrates, likely through a conformational change that distorts the central DNA binding tunnel. Moreover, we show that the FeS cluster is required for DNA2’s nuclease, helicase and ATPase activities. Our data also establish that oxidation of DNA2 impairs DNA binding in vitro, an effect that is reversible upon reduction. Unexpectedly, though, this redox-regulation is independent of the presence of the FeS cluster. Together, our study establishes an important structural role for the FeS cluster in human DNA2 and discovers a redox-regulatory mechanism to control DNA binding.

核酸酶/解旋酶DNA2在DNA复制，停滞的复制叉的修复和加工中起重要作用。DNA2包含一个铁硫（FeS）簇，在真核生物和相关细菌核酸酶中都保守。DNA维持蛋白中的FeS簇是结构完整性和/或充当氧化还原传感器所必需的。在这里，我们证明了FeS簇的丢失会影响人DNA2与特定DNA底物的结合，这可能是通过扭曲中央DNA结合通道的构象变化造成的。此外，我们表明，FeS簇是DNA2的核酸酶，解旋酶和ATPase活性所必需的。我们的数据还证实，DNA2的氧化作用会在体外损害DNA结合，这种作用在还原时是可逆的。但是，出乎意料的是，这种氧化还原调节与FeS团簇的存在无关。一起，