The structural basis of an NADP⁺-independent dithiol oxidase in FK228 biosynthesis.
The structural basis of an NADP⁺-independent dithiol oxidase in FK228 biosynthesis.
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FK228 生物合成中不依赖 NADP 的二硫醇氧化酶的结构基础
DOI：
10.1038/srep04145
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发表时间：
2014-02-20
影响因子：
4.6
通讯作者：
Zhou J
中科院分区：
文献类型：
--
作者：
Li J;Wang C;Zhang ZM;Cheng YQ;Zhou J
二硫键在天然产物中并不常见，对于热稳定性、细胞渗透性和生物活性至关重要。来自紫色色杆菌 No. 的 DepH 968 是一种 FAD 依赖性酶，负责催化 FK228 的二硫键形成，FK228 是一种被批准用于治疗皮肤 T 细胞淋巴瘤的抗癌前药。在这里，我们报道了 DepH 和 DepH 与底物类似物 S,S'-二甲基 FK228 分别在 1.82 Å 和 2.00 Å 络合的晶体结构。结构和生化分析表明，与已充分表征的低分子量硫氧还蛋白还原酶 (LMW TrxRs) 相比，DepH 是一种不依赖于 NADP+ 的二硫醇氧化酶。 DepH 不仅缺乏典型 LMW TrxR 中 NADP+ 结合所需的保守 GGGDXAXE 基序，而且还包含物理上阻碍 NADP+ 结合的 11 个残基序列。这些观察结果解释了 NADP+ 依赖性小分子二硫醇氧化酶和 NADP+ 依赖性硫氧还蛋白还原酶之间的差异，并为理解天然产物生物合成中涉及的二硫醇氧化酶的催化机制提供了见解。
The disulfide bond is unusual in natural products and critical for thermal stability, cell permeability and bioactivity. DepH fromChromobacterium violaceumNo. 968 is an FAD-dependent enzyme responsible for catalyzing the disulfide bond formation of FK228, an anticancer prodrug approved for the treatment of cutaneous T-cell lymphoma. Here we report the crystal structures of DepH and DepH complexed with a substrate analogue S,S'-dimethyl FK228 at 1.82 Å and 2.00 Å, respectively. Structural and biochemical analyses revealed that DepH, in contrast to the well characterized low molecular weight thioredoxin reductases (LMW TrxRs), is an NADP+-independent dithiol oxidase. DepH not only lacks a conserved GGGDXAXE motif necessary for NADP+binding in the canonical LMW TrxRs, but also contains a 11-residue sequence which physically impedes the binding of NADP+. These observations explain the difference between NADP+-independent small molecule dithiol oxidases and NADP+-dependent thioredoxin reductases and provide insights for understanding the catalytic mechanism of dithiol oxidases involved in natural product biosynthesis.