Department of Microbiology, Key Lab of Microbiology for Agricultural Environment, Ministry of Agriculture, College of Life Sciences, Nanjing Agricultural University, 210095 Nanjing, China.
College of Life Sciences, Huaibei Normal University, 235000 Huaibei, China.
J Agric Food Chem. 2020 Apr 15;68(15):4335-4345. doi: 10.1021/acs.jafc.0c00597. Epub 2020 Mar 31.
The phenylurea herbicide linuron is globally used and has caused considerable concern because it leads to environmental pollution. In this study, a highly efficient linuron-transforming strain sp. SMB was isolated, and a gene () responsible for the hydrolysis of linuron to 3,4-dichloroaniline and ,-dimethylhydroxylamine was cloned from the genome of strain SMB. The gene encodes an amidohydrolase, which shares 20-53% identity with other biochemically characterized amidohydrolases, except for the newly reported linuron hydrolase Phh (75%). The optimal conditions for the hydrolysis of linuron by LahB were determined to be pH 7.0 and 30 °C, and the value of LahB for linuron was 37.3 ± 1.2 μM. Although LahB and Phh shared relatively high identity, LahB exhibited a narrow substrate spectrum (specific for linuron) compared to Phh (active for linuron, diuron, chlortoluron, etc.). Sequence analysis and site-directed mutagenesis revealed that Ala261 of Phh was the key amino acid residue affecting the substrate specificity. Our study provides a new amidohydrolase for the specific hydrolysis of linuron.
苯基脲类除草剂利谷隆在全球范围内被广泛使用，因其会导致环境污染而备受关注。本研究从土壤中分离到一株高效的利谷隆转化菌株 sp. SMB， 并从该菌株的基因组中克隆到一个负责利谷隆水解生成 3,4-二氯苯胺和,-二甲基羟胺的基因 ()。 基因编码的酰胺水解酶与其他生化特性明确的酰胺水解酶具有 20-53%的同源性，除了新报道的利谷隆水解酶 Phh（75%）。LahB 水解利谷隆的最适条件为 pH 7.0 和 30°C，LahB 对利谷隆的 值为 37.3±1.2 μM。尽管 LahB 和 Phh 具有相对较高的同源性，但与 Phh（对利谷隆、敌草隆、氯噻隆等均有活性）相比，LahB 表现出较窄的底物谱（特异性水解利谷隆）。序列分析和定点突变揭示 Phh 的 Ala261 是影响底物特异性的关键氨基酸残基。本研究为利谷隆的特异性水解提供了一种新的酰胺水解酶。
