School of Marine Science and Technology, Harbin Institute of Technology at Weihai, Weihai, China.
Department of Traumatology, Wendeng Osteopath Hospital, Wendeng, China.
J Basic Microbiol. 2019 Sep;59(9):879-889. doi: 10.1002/jobm.201900240. Epub 2019 Jul 24.
Metallothionein (MT) is a low-molecular-weight protein with a high metal binding capacity and plays a key role in organism adaptation to heavy metals. In this study, a metallothionein gene was successfully cloned and sequenced from Antarctic sea-ice yeast Rhodotorula mucilaginosa AN5. Nucleotide sequencing and analysis revealed that the gene had four exons interrupted by three introns. MTs complementary DNA (named as RmMT) had an open reading frame of 321 bp encoding a 106 amino acid protein with a predicted molecular weight of 10.3 kDa and pI of 8.49. The number of amino acids and distribution of cysteine residues indicated that RmMT was a novel family of fungal MTs. Quantitative real-time polymerase chain reaction analysis showed that RmMT expression was elevated under copper-induced stress. The RmMT gene was transferred into E. coli and the RmMT expressing bacteria showed improved tolerance to copper ion and increased accumulation of heavy metals, such as Cu , Pb , Zn , Cd , and Ag . Moreover, in vitro studies, purified recombinant RmMT demonstrated that it could be used as a good scavenger of superoxide anion, hydroxyl, and 1,1-Diphenyl-2-picrylhydrazyl (DPPH) radicals. In summary, these results demonstrate that RmMT plays a key role in the tolerance and bioaccumulation of heavy metals.
金属硫蛋白（MT）是一种具有高金属结合能力的低分子量蛋白质，在生物体适应重金属方面起着关键作用。在本研究中，成功地从南极海冰酵母 Rhodotorula mucilaginosa AN5 中克隆并测序了一个金属硫蛋白基因。核苷酸测序和分析表明，该基因有四个外显子被三个内含子打断。MT 的 cDNA（命名为 RmMT）有一个 321bp 的开放阅读框，编码一个 106 个氨基酸的蛋白质，预测分子量为 10.3kDa，等电点为 8.49。氨基酸的数量和半胱氨酸残基的分布表明，RmMT 是真菌 MTs 的一个新家族。实时定量聚合酶链反应分析表明，RmMT 在铜诱导应激下表达上调。RmMT 基因被转入大肠杆菌，表达 RmMT 的细菌对铜离子的耐受性提高，对重金属如 Cu、Pb、Zn、Cd 和 Ag 的积累增加。此外，体外研究表明，纯化的重组 RmMT 可以作为超氧阴离子、羟基和 1,1-二苯基-2-苦基肼（DPPH）自由基的良好清除剂。总之，这些结果表明 RmMT 在重金属的耐受和生物积累中起着关键作用。
