THIOPHENE-DEGRADING ESCHERICHIA-COLI MUTANTS POSSESS SULFONE OXIDASE ACTIVITY AND SHOW ALTERED RESISTANCE TO SULFUR-CONTAINING ANTIBIOTICS
THIOPHENE-DEGRADING ESCHERICHIA-COLI MUTANTS POSSESS SULFONE OXIDASE ACTIVITY AND SHOW ALTERED RESISTANCE TO SULFUR-CONTAINING ANTIBIOTICS
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DOI：
10.1128/aem.56.10.3179-3185.1990
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发表时间：
1990-10-01
影响因子：
4.4
通讯作者：
CLARK, DP
中科院分区：
文献类型：
--
作者：
JUHL, MJ;CLARK, DP
我们以前分离的大肠杆菌的突变体，表现出增加的杂环呋喃和噻吩底物的氧化。我们现在已经发现，携带thdA突变的菌株表达一种新的酶活性，其氧化含有砜（SO2）部分的各种底物。杂环砜（例如，四亚甲基砜）和简单的脂族砜（例如，乙基砜）被氧化。thdA突变体比野生型菌株对芳砜类抗生素如氨苯砜更耐药。相反，他们表现出增加的敏感性，硫醇，一种环状抗生素含有硫的硫化物氧化水平。几个新的thd A突变体等位基因通过选择增加氧化的各种脂肪族硫化合物分离。这些新的thdA突变体表现出类似的砜氧化酶活性和相同的地图位置（在10.7分钟）作为原始的thdA1突变。组成型fadR突变是thdA介导的硫化合物氧化的表型表达所必需的。然而，thdA指导的砜氧化酶活性的表达不依赖于fadR。thdC和thdD突变可能防止噻吩衍生物的毒性，而不是赋予改善的代谢能力。
We have previously isolated mutants of Escherichia coli which show increased oxidation of heterocyclic furan and thiophene substrates. We have now found that strains carrying the thdA mutation express a novel enzyme activity which oxidizes a variety of substrates containing a sulfone (SO2) moiety. Both heterocyclic sulfones (e.g., tetramethylene sulfone) and simple aliphatic sulfones (e.g., ethyl sulfone) were oxidaized. The thdA mutants were more resistant than wild-type strains to aromatic sulfone antibiotics such as dapsone. In contrast they showed increased susceptibility to thiolutin, a cyclic antibiotic containing sulfur at the sulfide level of oxidation. Several new thd A mutant alleles were isolated by selecting for increased oxidation of various aliphatic sulfur compounds. These new thdA mutants showed similar sulfone oxidase activity and the same map location (at 10.7 min) as the original thdA1 mutation. The constitutive fadR mutation was required for the phenotypic expression of thdA-mediated oxidation of sulfur compounds. However, the thdA-directed expression of sulfone oxidase activity was not fadR dependent. The thdC and thdD mutations probably protect against the toxicity of thiophene derivatives rather than conferring improved metabolic capability.