Enhancement of bacterial mutagenicity of bifunctional alkylating agents by expression of mammalian glutathione S-transferase.
Enhancement of bacterial mutagenicity of bifunctional alkylating agents by expression of mammalian glutathione S-transferase.
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通过表达哺乳动物谷胱甘肽 S-转移酶增强双功能烷化剂的细菌致突变性。
DOI：
10.1021/tx00045a019
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发表时间：
1995
影响因子：
4.1
通讯作者：
Guengerich,FP
中科院分区：
文献类型：
--
作者：
Thier,R;Müller,M;Taylor,JB;Pemble,SE;Ketterer,B;Guengerich,FP
最近，我们将含有大鼠GSH S-转移酶（GST）5-5 cDNA的质粒载体pKK233-2插入鼠伤寒沙门氏菌TA1535中，发现这些细菌[GST 5-5（+）]在添加乙烯或二卤甲烷时表达该蛋白并产生突变[Thier, R., Taylor, JB, Pemble, S. E., Ketterer, B., Persmark, M., Humphreys, WG 和 Guengerich, F. P.(1993) Proc.国家。阿卡德。科学。美国。 [90, 8576-8580]，暴露于已知的 GST 5-5 底物 l，2-环氧-3-(4'-硝基苯氧基)丙烷后，GST 5-5 (+) 菌株显示出比反向转染 cDNA 克隆的细菌更少的突变体 [GST 5-5 (—)]，表明 GST 5-5 具有保护作用。然而，当添加 1,2,3,4-二环氧丁烷（丁二烯二环氧化物）或 1,2-环氧-4-溴丁烷时，GST 5-5 (+) 菌株中的突变显着增强[与 GST 5-5 (-) 相比]。 GST 5-5 (+) 和 GST 5-5 (-) 细菌染色剂对 1, 2-环氧丙烷、3, 4-环氧-1-丁烯和 1, 4-二溴丁烷表现出相似的反应。结果表明，一些双功能活化丁烷通过 GSH 结合转化为诱变产物。我们还发现 GST 5-5 (+) 菌株对 1, 4-二溴-2, 3-环氧丁烷、1, 2-环氧-3-溴丙烷（表溴醇）和 (±)-1, 4-二溴-2, 3-二羟基丁烷表现出增强的致突变性。认为5元硫鎓离子可能与致突变性有关。模型硫铊化合物在 pH 7.4 的水溶液和缓慢烷基化的 4-(4-硝基苄基)吡啶中对水解相当稳定。硫上羟基β的存在不会增强反应性。涉及表锍离子的机制被认为更有可能。该系统还考虑了有毒农药 1,2-二溴-3-氯丙烷 (DBCP) 的潜在氧化产物。 DBCP 本身在两种菌株中给出了相当相似的结果。其他人报道，DBCP 的氧化以及 GST 催化的 GSH 结合是致突变性所必需的 [Simula, T. P., Glancey, MJ, Soderlund, EJ, Dybing, E., and Wolf, CR (1993) Carcinogenesis 14, 2303-2307]。推定的氧化产物 1, 2-二溴丙酸在两个菌株之间没有显示出差异。然而，1, 3-二氯丙酮（假定的氧化产物 1-溴-3-氯丙酮的模型）在 GST5-5 (+) 菌株中的致突变性要大得多。
Recently, we inserted the plasmid vector pKK233-2 containing rat GSH S-transferase (GST) 5-5 cDNA into Salmonella typhimurium TA1535 and found that these bacteria [GST 5-5 (+)] expressed the protein and produced mutations when ethylene or methylene dihalides were added [Thier, R., Taylor, JB, Pemble, S. E., Ketterer, B., Persmark, M., Humphreys, WG, and Guengerich, F. P.(1993) Proc. Natl. Acad. Sci. U. SA. 90, 8576-8580], After exposure to the known GST 5-5 substrate l, 2-epoxy-3-(4'-nitrophenoxy) propane, the GST 5-5 (+) strain showed fewer mutants than the bacteria transfected with the cDNA clone in a reverse orientation [GST 5-5 (—)], suggesting a protective role of GST 5-5. However, mutations were considerably enhanced in the GST 5-5 (+) strain [as compared to GST 5-5 (—)] when 1, 2, 3, 4-diepoxybutane (butadiene diepoxide) or l, 2-epoxy-4-bromobutane was added. The GST 5-5 (+) and GST 5-5 (-) bacterial stains showed similar responses to 1, 2-epoxypropane, 3, 4-epoxy-1-butene, and 1, 4-dibromobutane. The results suggest that some bifunctional activated butanes are transformed to mutagenic products through GSH conjugation. We also found that the GST 5-5 (+) strain showed enhanced mutagenicity with l, 4-dibromo-2, 3-epoxybutane, 1, 2-epoxy-3-bromopropane (epibromohydrin), and (±)-l, 4-dibromo-2, 3-dihydroxybutane. The possibility was considered that a 5-membered thialonium ion may be involved in the mutagenicity. Model thialonium compounds were rather stable to hydrolysis in aqueous solution at pH 7.4 and slowly alkylated 4-(4-nitrobenzyl) pyridine. Thepresence of a hydroxyl group ß to the sulfur did not enhance reactivity. Mechanisms involving episulfonium ions are considered more likely. Potential oxidation products of the toxic pesticide l, 2-dibromo-3-chloropropane (DBCP) were also considered in this system. DBCP itself gave rather similar results inthe two strains. Others have reported that oxidation of DBCP is required for mutagenicity, along with GST-catalyzed GSH conjugation [Simula, T. P., Glancey, MJ, Soderlund, EJ, Dybing, E., and Wolf, CR (1993) Carcinogenesis 14, 2303-2307]. The putative oxidation product 1, 2-dibromopropional did not show a difference between the two strains. However, 1, 3-dichloro-acetone, a model for the putative oxidation product l-bromo-3-chloroacetone, was considerably more mutagenic in the GST5—5 (+) strain.