Cloning, expression, and characterization of cadmium-induced metallothionein-2 from the earthworms Metaphire posthuma and Polypheretima elongata

Shih Hsiung Liang, Yu Ping Jeng, Yuh Wen Chiu, Jiun Hong Chen, Bao Sen Shieh, Chien Yen Chen, Chien Cheng Chen

研究成果: Article同行評審

14 引文 斯高帕斯(Scopus)

摘要

In this study we report the sequences of MT-2 cDNA from two species of Megascoleidae earthworms, Metaphire posthuma and Polypheretima elongata, by mRNA differential display after exposure of the organisms to cadmium. Complementary (c)DNA was verified as the MT-2 gene by the characteristics of its predicted translation product, namely a high cysteine content, conserved CXC motifs, and a molecular weight of around 8 kDa. Amino acid sequence alignment revealed a conserved TKCCG in the cloned MT-2 of both megascolecid earthworms instead of the corresponding conserved TQCCG found in lumbricid earthworms. The cDNAs corresponding to the two megascolecid MT-2 genes were expressed, and the MT-2 proteins were purified for biochemical characterization. The binding of Cu2+ exhibited monophasic kinetics and those of Zn2+ and Cd2+ biphasic kinetics. The proteins bound more tightly to Cd2+ than to Zn2+ and more tightly still to Cu2+. Zn-MT and apo-MT were the most effective at scavenging free radicals, followed by Cd-MT. In conclusion, MT-2s from M. posthuma and P. elongata showed unique sequence features compared to those of lumbricid earthworms. These earthworms could be used to evaluate heavy-metal pollution in soil due to the inducible MT-2 by cadmium exposure.

原文English
頁(從 - 到)349-357
頁數9
期刊Comparative Biochemistry and Physiology - C Toxicology and Pharmacology
149
發行號3
DOIs
出版狀態Published - 2009 四月

All Science Journal Classification (ASJC) codes

  • Biochemistry
  • Physiology
  • Toxicology
  • Cell Biology
  • Health, Toxicology and Mutagenesis

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