摘要
金属硫蛋白(MT)是一类富含半胱氨酸的小分子蛋白质,其能够以硫醇基团结合多种重金属和稀土金属离子从而缓解细胞的金属离子压力.本文将来源于稀土钇超富集的美洲商陆和Penicillium sp.ZD28的6条钇响应的MTs为目标基因,将其与大肠杆菌细胞表面膜蛋白lpp'OmpA融合表达构建工程菌,SDS-PAGE和Western blot结果表明目的基因成功表达并定位在细胞膜表面.MTs在大肠杆菌细胞膜表面展示的工程菌株能够显著提高其对钇的耐受性.然而,其对钇的吸附效果不一,其中来源于美洲商陆的MT2-2的工程菌对钇的吸附效果显著高于对照组,其钇吸附容量约为对照组的2倍;进一步将其应用到赣南稀土尾矿废水的钇吸附,结果表明,废水经MT2-2工程菌二次吸附后,钇吸附率达93%.然而,废水中高含量的Al^(3+)是钇吸附的主要竞争性离子.未来,还需深入研究发掘钇特异性结合蛋白质标签,从而提高工程菌对钇的特异性吸附.
Metallothionein(MT) is a kind of small molecule protein rich in cysteine,which can bind various heavy metals and rare earth metal ions with mercaptan groups to relieve the pressure of metal ions on cells.In this paper,six yttrium-responsive MTs genes were fused with the surface membrane protein lpp'OmpA of Escherichia coli to construct engineering bacteria.The MTs genes derived from Phytolacca americana and Penicillium sp.ZD28,which are the rare earth yttrium hyperaccumulators.SDS-PAGE and Western blot results showed that the target genes were successfully expressed and localized on the surface of cell membrane.The engineering bacteria have stronger tolerance to yttrium.However,its adsorption capability of yttrium varies.Among them,the adsorption of yttrium by MT2-2 engineering bacteria was significantly higher than that of control group,and its yttrium adsorption capacity was about twice that of control group.It was further applied to yttrium adsorption from rare earth tailings wastewater in southern Jiangxi Province.The results showed that the yttrium adsorption rate reached 93% after twice adsorption by MT2-2 engineering bacteria.However,the high content of Al^(3+) in wastewater is the main competitive ion for yttrium adsorption.In the future,further research should be conducted to explore yttrium-specific binding protein tags,so as to improve the selective adsorption of yttrium by engineered bacteria.
作者
杨蕾
吴心怡
肖凯
颜日明
张志斌
王伟英
YANG Lei;WU Xinyi;XIAO Kai;YAN Riming;ZHANG Zhibin;WANG Weiying(Key Laboratory of Biodiversity Conservation and Bioresources Utilization of Jiangxi Province,College of Life Sciences,Jiangxi Normal University,Nanchang 330022;Hydrogeological Brigade of Jiangxi Geological Bureau,Nanchang 330000)
出处
《环境科学学报》
CAS
CSCD
北大核心
2024年第7期49-56,共8页
Acta Scientiae Circumstantiae
基金
江西省自然科学基金项目(No.20192BAB214002)
江西省生物多样性保护与资源利用开放基金项目(No.YRD201907)。
关键词
金属硫蛋白
细胞表面展示工程菌
钇吸附
特异性吸附
metallothionein
surface-display engineered bacteria
yttrium adsorption
specific adsorption
