Crystal structure of a Bombyx mori sigma-class glutathione transferase exhibiting prostaglandin E synthase activity.
Crystal structure of a Bombyx mori sigma-class glutathione transferase exhibiting prostaglandin E synthase activity.
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DOI：
10.1016/j.bbagen.2013.02.021
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发表时间：
2013-06
期刊：
影响因子：
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通讯作者：
Kohji Yamamoto;A. Higashiura;Mamoru Suzuki;K. Aritake;Y. Urade;N. Uodome;A. Nakagawa
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文献类型：
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作者：
Kohji Yamamoto;A. Higashiura;Mamoru Suzuki;K. Aritake;Y. Urade;N. Uodome;A. Nakagawa
谷胱甘肽转移酶（GST）是解毒酶的主要家族成员。在这里，我们报告了家蚕的sigma类GST，bmGSTS 1，方法用同步辐射和分子置换法分别在1.9 nm和1.7 nm处测定了bmGSTS 1及其与谷胱甘肽复合物的结构。bmGSTS 1的三维结构表明，它作为二聚体存在，并且就其二级和三级结构而言，在结构上与其他GST相似。虽然bmGSTS 1与前列腺素D合成酶的结构也有惊人的相似性，但我们惊奇地发现bmGSTS 1可以将前列腺素H2转化为E2形式。bmGSTS 1与谷胱甘肽复合物的比较表明，结合谷胱甘肽定位于谷胱甘肽结合位点（G-位点）。bmGSTS 1突变体的定点突变表明，G位点中的氨基酸残基Tyr 8、Leu 14、Trp 39、Lys 43、Gln 50、Met 51、Gln 63和Ser 64有助于催化活性。结论我们确定了具有前列腺素E合酶活性的bmGSTS 1的三级结构。一般意义据我们所知，这些结果是昆虫中前列腺素合酶活性的首次报道。
BACKGROUNDGlutathione transferases (GSTs) are members of a major family of detoxification enzymes. Here, we report the crystal structure of a sigma-class GST of Bombyx mori, bmGSTS1, to gain insight into the mechanism catalysis.METHODSThe structure of bmGSTS1 and its complex with glutathione were determined at resolutions of 1.9Å and 1.7Å by synchrotron radiation and the molecular replacement method.RESULTSThe three-dimensional structure of bmGSTS1 shows that it exists as a dimer and is similar in structure to other GSTs with respect to its secondary and tertiary structures. Although striking similarities to the structure of prostaglandin D synthase were also detected, we were surprised to find that bmGSTS1 can convert prostaglandin H2into its E2form. Comparison of bmGSTS1 with its glutathione complex showed that bound glutathione was localized to the glutathione-binding site (G-site). Site-directed mutagenesis of bmGSTS1 mutants indicated that amino acid residues Tyr8, Leu14, Trp39, Lys43, Gln50, Met51, Gln63, and Ser64 in the G-site contribute to catalytic activity.CONCLUSIONWe determined the tertiary structure of bmGSTS1 exhibiting prostaglandin E synthase activity.GENERAL SIGNIFICANCEThese results are, to our knowledge, the first report of a prostaglandin synthase activity in insects.