Molecular Cloning and Characterization of a New Cold-active Extradiol Dioxygenase from a Metagenomic Library Derived from Polychlorinated Biphenyl-contaminated Soil

作者：Ren He-jun^*; Lu Yang; Zhou Rui; Dai Chun-yan; Wang Yan; Zhang Lan-ying

来源：Chemical Research in Chinese Universities, 2012, 28(4): 666-671.

• Extradiol dioxygenase
• Metagenome
• Cold-active enzyme
• Gene cloning
• Functional characterization

To find new extradiol dioxygenases(EDOs, EC 1.13.11.2), a metagenomics library was constructed from polychlorinated biphenyl-contaminated soil and was screened for some dioxygenase with aromatic ring cleavage activity. A novel EDO, designated as BphC_A, was identified and heterologously expressed in Escherichia coli. The deduced amino acid sequence of BphC_A exhibited a homology of less than 60% with other known EDOs. Phylogenetic analysis of BphC_A suggests that the protein is a novel member of the EDO family. The enzyme exhibits higher substrate affinity and catalytic efficiency toward 3-methylcatechol than toward 2,3-dihydroxybiphenyl or catechol, the preferred substrate of other known EDOs. The optimum activity of purified BphC_A occurred at pH=8.5 and 35 degrees C, and BphC_A showed more than 40% of its initial activity at 5 degrees C. The activity of purified BphC_A was significantly induced by Mn2+ and slightly reduced by Al3+, Cu2+ and Zn2+.

• 出版日期2012-7-25
• 单位吉林省农业科学院; 吉林大学