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Identification and subcellular localization of a novel Cu,Zn superoxide dismutase of Mycobacterium tuberculosis
Author(s) -
Wu C.H.Herbert,
Tsai-Wu Jyy-Jih,
Huang Yung-Tzung,
Lin Ching-Yi,
Lioua Gunn-Guang,
Lee Feng-Jen S.
Publication year - 1998
Publication title -
febs letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.593
H-Index - 257
eISSN - 1873-3468
pISSN - 0014-5793
DOI - 10.1016/s0014-5793(98)01373-8
Subject(s) - superoxide dismutase , mycobacterium tuberculosis , subcellular localization , tuberculosis , chemistry , identification (biology) , microbiology and biotechnology , dismutase , biochemistry , biology , pathology , medicine , enzyme , cytoplasm , botany
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 .