Screening of metagenomic and genomic libraries reveals three classes of bacterial enzymes that overcome the toxicity of acrylate.
Screening of metagenomic and genomic libraries reveals three classes of bacterial enzymes that overcome the toxicity of acrylate.
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DOI：
10.1371/journal.pone.0097660
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发表时间：
2014
期刊：
影响因子：
3.7
通讯作者：
Johnston AW
中科院分区：
文献类型：
--
作者：
Curson AR;Burns OJ;Voget S;Daniel R;Todd JD;McInnis K;Wexler M;Johnston AW
大量的丙烯酸酯是通过微生物裂解高度丰富的海洋生物保护剂二甲基磺基丙酸酯而产生的，这是海洋硫循环中的一个重要过程。丙烯酸酯可以抑制细菌生长，可能是通过将其转化为高毒性分子丙烯酰辅酶A。先前的工作确定了由基因acuI编码的丙烯酰辅酶A还原酶，其对于赋予细菌在丙烯酸酯存在下生长的能力是重要的。然而，有些细菌缺乏acuI，相反，许多在常规环境中可能不会遇到丙烯酸酯的细菌确实含有这种基因。因此，我们试图确定新的基因，可能赋予耐丙烯酸酯。为了做到这一点，我们使用宏基因组和基因组文库的功能筛选，以确定新的基因，纠正E。大肠杆菌突变体，该突变体在acuI中有缺陷，因此对丙烯酸酯超敏感。宏基因组文库产生了两种克服这种毒性的基因。大多数编码类似AcuI的酶，但彼此之间和先前批准的AcuI酶之间存在显着的序列差异。另一个宏基因组基因arkA在芽孢杆菌和相关细菌中具有非常近的亲属，并且被预测编码与FabK相同家族的烯酰-酰基载体蛋白还原酶，FabK催化某些致病性厚壁菌中脂肪酸生物合成的最后一步。新鞘氨醇菌属是一种缺乏acuI和arkA的代谢多功能α变形杆菌，其基因组文库产生了vutD和vutE，这两个基因共同赋予丙烯酸酯抗性。这些编码顺序步骤中的氧化催化缬氨酸的途径中，显着，甲基丙烯酰辅酶A是一种有毒的中间体。这些发现扩大了acuI基因编码功能性丙烯酰辅酶A还原酶的细菌的范围，并确定了新的酶，这些酶可以类似地通过去除有毒产物丙烯酰辅酶A来赋予丙烯酸酯抗性。
Acrylate is produced in significant quantities through the microbial cleavage of the highly abundant marine osmoprotectant dimethylsulfoniopropionate, an important process in the marine sulfur cycle. Acrylate can inhibit bacterial growth, likely through its conversion to the highly toxic molecule acrylyl-CoA. Previous work identified an acrylyl-CoA reductase, encoded by the gene acuI, as being important for conferring on bacteria the ability to grow in the presence of acrylate. However, some bacteria lack acuI, and, conversely, many bacteria that may not encounter acrylate in their regular environments do contain this gene. We therefore sought to identify new genes that might confer tolerance to acrylate. To do this, we used functional screening of metagenomic and genomic libraries to identify novel genes that corrected an E. coli mutant that was defective in acuI, and was therefore hyper-sensitive to acrylate. The metagenomic libraries yielded two types of genes that overcame this toxicity. The majority encoded enzymes resembling AcuI, but with significant sequence divergence among each other and previously ratified AcuI enzymes. One other metagenomic gene, arkA, had very close relatives in Bacillus and related bacteria, and is predicted to encode an enoyl-acyl carrier protein reductase, in the same family as FabK, which catalyses the final step in fatty-acid biosynthesis in some pathogenic Firmicute bacteria. A genomic library of Novosphingobium, a metabolically versatile alphaproteobacterium that lacks both acuI and arkA, yielded vutD and vutE, two genes that, together, conferred acrylate resistance. These encode sequential steps in the oxidative catabolism of valine in a pathway in which, significantly, methacrylyl-CoA is a toxic intermediate. These findings expand the range of bacteria for which the acuI gene encodes a functional acrylyl-CoA reductase, and also identify novel enzymes that can similarly function in conferring acrylate resistance, likely, again, through the removal of the toxic product acrylyl-CoA.
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影响因子：
5.4
作者：
Herrmann, G;Selmer, T;Buckel, W
通讯作者：
Buckel, W
DOI：
10.1099/ijs.0.02301-0
发表时间：
2003-01-01
影响因子：
2.8
作者：
Fujii, K;Satomi, M;Kikuchi, S
通讯作者：
Kikuchi, S
DOI：
10.1099/00207713-47-1-191
发表时间：
1997-01-01
期刊：
INTERNATIONAL JOURNAL OF SYSTEMATIC BACTERIOLOGY
影响因子：
--
作者：
Balkwill, DL;Drake, GR;Spadoni, CM
通讯作者：
Spadoni, CM
影响因子：
11
作者：
Curson, Andrew R. J.;Sullivan, Matthew J.;Johnston, Andrew W. B.
通讯作者：
Johnston, Andrew W. B.
影响因子：
11
作者：
Curson, Andrew R. J.;Sullivan, Matthew J.;Johnston, Andrew W. B.
通讯作者：
Johnston, Andrew W. B.