College of Life Sciences, Hebei Basic Science Center for Biotic Interaction, Hebei University, Baoding, Hebei 071002, China.
College of Chemistry and Chemical Engineering, Research Institute of Industrial Hazardous Waste Disposal and Resource Utilization, Southwest Petroleum University, Chengdu, Sichuan 610500, China.
Int J Biol Macromol. 2024 Nov;281(Pt 3):136329. doi: 10.1016/j.ijbiomac.2024.136329. Epub 2024 Oct 8.
Polyacrylamide (PAM) is a high molecular weight polymer with extensive applications. However, inefficient natural degradation of PAM results in its environmental accumulation. Here, using multi-omics analysis, we constructed the PAM biodegradation pathway in Klebsiella sp. PCX, an efficient PAM-degrading bacterium. Subsequently, two unclassified amidohydrolases (PCX00451 and PCX04581) were identified as key factors for rapid PAM biodegradation, both of which possessed much higher hydrolysis efficiency for PAM than for small molecule amide compounds. Besides, crystal structures of PCX00451 and PCX04581 were solved. Both two amidohydrolases were consisted with a twisted triosephosphateisomerase (TIM)-barrel and a smaller β-sandwich domain. And their binding pockets were in the conserved metal center of TIM-barrel domain. Moreover, Asp267 of PCX00451 and Asp282 of PCX04581 were examined as active sites for acid/base catalysis. Our research characterized the molecular mechanisms of two efficient amidohydrolases, providing theoretical basis and valuable tools for PAM bioremediation.
聚丙烯酰胺（PAM）是一种高分子量聚合物，具有广泛的应用。然而，PAM 不能被自然有效地降解，导致其在环境中积累。在这里，我们使用多组学分析，构建了高效 PAM 降解菌 Klebsiella sp. PCX 中的 PAM 生物降解途径。随后，我们鉴定出了两种未分类的酰胺水解酶（PCX00451 和 PCX04581），它们是快速 PAM 生物降解的关键因素，这两种酶对 PAM 的水解效率都远高于小分子酰胺化合物。此外，我们还解析了 PCX00451 和 PCX04581 的晶体结构。这两种酰胺水解酶均由扭曲的三磷酸甘油醛异构酶（TIM）-桶和较小的β-三明治结构域组成。它们的结合口袋位于 TIM-桶结构域的保守金属中心。此外，我们还研究了 PCX00451 的 Asp267 和 PCX04581 的 Asp282 作为酸碱催化的活性位点。我们的研究阐明了两种高效酰胺水解酶的分子机制，为 PAM 的生物修复提供了理论依据和有价值的工具。
