Identification and subcellular localization of a novel Cu,Zn superoxide dismutase of Mycobacterium tuberculosis

FEBS Letters

Lee, Feng-Jen S.²  Lin, Ching-Yi²  Tsai-Wu, Jyy-Jih¹  Lioua, Gunn-Guang²  Huang, Yung-Tzung²  Wu, C.H.Herbert² 

[1] Department of Clinical Medicine, National Taiwan University Hospital, Taipei 100, Taiwan;Institute of Molecular Medicine, School of Medicine, National Taiwan University, 7 Chung Shan South Road, Taipei 100, Taiwan

关键词: Cu;    Zn superoxide dismutase;    Periplasmic;    Gram-positive bacterium;   

DOI  :  10.1016/S0014-5793(98)01373-8

学科分类：生物化学/生物物理

来源: John Wiley & Sons Ltd.

【 摘 要 】

Periplasmic copper, zinc superoxide dismutases (Cu,ZnSOD) of several Gram-negative pathogens have been shown to play an important role in protection against exogenous superoxide radicals and in determining virulence of the pathogens. Here we report the cloning and characterization of the sodC gene, encoding Cu,ZnSOD, from the Gram-positive Mycobacterium tuberculosis. The predicted protein sequence contains 240 amino acids with a putative signal peptide at the N-terminus and shows ∼25% identity to other bacterial sodC. Recombinant proteins of a full-length sodC and a truncated form lacking the putative signal peptide were overexpressed in Escherichia coli and affinity purified. Renatured recombinant M. tuberculosis sodC protein possessed characteristics of a Cu,ZnSOD. Immunoblotting with an antiserum against the recombinant M. tuberculosis Cu,ZnSOD allowed detection of a single polypeptide in the lysate of M. tuberculosis. This polypeptide has a similar size as the recombinant protein without the putative signal peptide indicating that the endogenous Cu,ZnSOD in M. tuberculosis might be processed and secreted. Furthermore, immunogold electron microscopic image showed that Cu,ZnSOD is located in the periphery of M. tuberculosis. The enzymatic activity and subcellular localization of this novel Cu,ZnSOD suggest that it may play a role in determining virulence of M. tuberculosis.

【 授权许可】

Unknown