Crystal Structure of a Eukaryotic GEN1 Resolving Enzyme Bound to DNA.
Crystal Structure of a Eukaryotic GEN1 Resolving Enzyme Bound to DNA.
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DOI：
10.1016/j.celrep.2015.11.042
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发表时间：
2015-12-22
期刊：
影响因子：
8.8
通讯作者：
Lilley DMJ
中科院分区：
文献类型：
--
作者：
Liu Y;Freeman ADJ;Déclais AC;Wilson TJ;Gartner A;Lilley DMJ
我们目前的晶体结构的连接解析酶GEN 1结合到DNA在2.5纳米分辨率。GEN 1蛋白的结构揭示了它具有精心设计的FEN-XPG家族折叠，该折叠因其在四向连接解析中的作用而被修饰。晶体中的功能单元是与拆分切割产物结合的活性GEN 1单体，两个螺旋臂具有广泛的DNA结合界面。在晶格内，GEN 1二聚体界面将两种产物并置，由此它们可以重新连接成四向连接，其结构与溶液中测定的结构一致。重新连接需要中心的DNA结构的一些开口，与高锰酸盐探针和2-氨基嘌呤荧光一致。该结构表明，DNA结构的松弛伴随着切割，这表明第二链切割是如何加速的，以确保接合处的有效分辨率。GEN 1与含有两个垂直DNA螺旋的拆分产物一起结晶GEN 1共享FEN 1超家族折叠，与含有两个金属离子的活性位点GEN 1形成二聚体，该二聚体将两个产物并置在底物样复合物中。呈现真菌GEN 1霍利迪连接分解酶的晶体结构。GEN 1与裂解产物结合，包含两个连接的连接臂。两个GEN 1分子二聚化以并置两个产物，使得它们可以简单地重新连接以形成连接。
We present the crystal structure of the junction-resolving enzyme GEN1 bound to DNA at 2.5 Å resolution. The structure of the GEN1 protein reveals it to have an elaborated FEN-XPG family fold that is modified for its role in four-way junction resolution. The functional unit in the crystal is a monomer of active GEN1 bound to the product of resolution cleavage, with an extensive DNA binding interface for both helical arms. Within the crystal lattice, a GEN1 dimer interface juxtaposes two products, whereby they can be reconnected into a four-way junction, the structure of which agrees with that determined in solution. The reconnection requires some opening of the DNA structure at the center, in agreement with permanganate probing and 2-aminopurine fluorescence. The structure shows that a relaxation of the DNA structure accompanies cleavage, suggesting how second-strand cleavage is accelerated to ensure productive resolution of the junction. GEN1 crystallized with a resolution product containing two perpendicular DNA helices GEN1 shares the FEN1 superfamily fold, with a two-metal ion-containing active site GEN1 forms a dimer that juxtaposes two products in a substrate-like complex A resulting model of a GEN1-junction complex is supported by solution experiments Liu et al. present the crystal structure of a fungal GEN1 Holliday junction-resolving enzyme. GEN1 is bound to a product of cleavage, comprising two connected arms of the junction. Two GEN1 molecules dimerize to juxtapose two products such that they can be simply reconnected to form a junction.