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The Mycobacterium tuberculosis ino1 gene is essential for growth and virulence
Author(s) -
Movahedzadeh Farahnaz,
Smith Debbie A.,
Norman Richard A.,
Dinadayala Premkumar,
MurrayRust Judith,
Russell David G.,
Kendall Sharon L.,
Rison Stuart C. G.,
McAlister Mark S. B.,
Bancroft Gregory J.,
McDonald Neil Q.,
Daffe Mamadou,
AvGay Yossef,
Stoker Neil G.
Publication year - 2004
Publication title -
molecular microbiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.857
H-Index - 247
eISSN - 1365-2958
pISSN - 0950-382X
DOI - 10.1046/j.1365-2958.2003.03900.x
Subject(s) - biology , virulence , mycobacterium tuberculosis , microbiology and biotechnology , tuberculosis , gene , mycobacterium , genetics , virology , bacteria , medicine , pathology
Summary Inositol is utilized by Mycobacterium tuberculosis in the production of its major thiol and of essential cell wall lipoglycans. We have constructed a mutant lacking the gene encoding inositol‐1‐phosphate synthase ( ino1 ), which catalyses the first committed step in inositol synthesis. This mutant is only viable in the presence of extremely high levels of inositol. Mutant bacteria cultured in inositol‐free medium for four weeks showed a reduction in levels of mycothiol, but phosphatidylinositol mannoside, lipomannan and lipoarabinomannan levels were not altered. The ino1 mutant was attenuated in resting macrophages and in SCID mice. We used site‐directed mutagenesis to alter four putative active site residues; all four alterations resulted in a loss of activity, and we demonstrated that a D310N mutation caused loss of the active site Zn 2+ ion and a conformational change in the NAD + cofactor.