Lipid modification of the Cu,Zn superoxide dismutase from Mycobacterium tuberculosis.
The leader sequence of Mycobacterium tuberculosis Cu,Zn superoxide dismutase (Cu,ZnSOD) contains a prokaryotic membrane lipoprotein attachment site. In the present study, we have found that the protein, which exhibits detectable SOD activity, is lipid-modified and associated with the bacterial membrane when expressed either in M. tuberculosis or in Escherichia coli. These results provide the first demonstration of lipid modification of a Cu,ZnSOD. An analysis of the sodC genes present in available databases indicates that the same signal for lipid modification is also present in the sodC gene products from other mycobacteria and Gram-positive bacteria and, uniquely, in two distinct sodC gene products from the Gram-negative bacterium Salmonella typhimurium. Evidence is also provided for an up-regulation of M. tuberculosis sodC in response to phagocytosis by human macrophages, suggesting that Cu,ZnSOD is involved in the mechanisms that facilitate mycobacterial intracellular growth.
D'orazio
M
M
Department of Biology, University of Rome Tor Vergata, Via della Ricerca Scientifica, 00133 Rome, Italy.
Folcarelli
S
S
Mariani
F
F
Colizzi
V
V
Rotilio
G
G
Battistoni
A
A
D002462:Cell Membrane / Q000378:metabolism; D017931:DNA Primers / Q000737:chemistry; D004926:Escherichia coli / Q000201:enzymology; D029968:Escherichia coli Proteins; D006801:Humans; D008264:Macrophages / Q000166:cytology / Q000382:microbiology; D009169:Mycobacterium tuberculosis / Q000201:enzymology* / Q000235:genetics; D019308:Palmitic Acid / Q000378:metabolism*; D010446:Peptide Fragments / Q000737:chemistry / Q000378:metabolism; D010587:Phagocytosis; D016133:Polymerase Chain Reaction; D013482:Superoxide Dismutase / Q000235:genetics / Q000378:metabolism*; D015854:Up-Regulation
D017931:DNA Primers; D029968:Escherichia coli Proteins; D010446:Peptide Fragments; D019308:Palmitic Acid; D013482:Superoxide Dismutase; C116114:sodC protein, E coli