Related Experiment Videos
p-Hydroxybenzoic acid synthesis in Mycobacterium tuberculosis.
Gustavo Stadthagen1, Jana Korduláková, Ruth Griffin
1Unité deGénétique Mycobactérienne, Institut Pasteur, 75015, Paris, France.
The Journal of Biological Chemistry
|October 8, 2005
Summary
Mycobacterium tuberculosis produces virulence factors from p-hydroxybenzoic acid. Researchers identified Rv2949c as the enzyme responsible for creating this essential precursor from chorismate.
Area of Science:
- Microbiology
- Biochemistry
- Molecular Biology
Background:
- Glycosylated p-hydroxybenzoic acid methyl esters and phenolphthiocerol glycolipids are key virulence factors in Mycobacterium tuberculosis.
- These molecules are believed to originate from p-hydroxybenzoic acid, but its biosynthetic pathway in mycobacteria was previously unknown.
Purpose of the Study:
- To elucidate the origin and biosynthesis of p-hydroxybenzoic acid in Mycobacterium tuberculosis.
- To identify the specific enzyme responsible for producing p-hydroxybenzoic acid.
Main Methods:
- Characterization of a transposon mutant of M. tuberculosis lacking p-hydroxybenzoic acid derivatives.
- Identification of the insertion site in the Rv2949c gene.
- Recombinant expression and purification of the Rv2949c enzyme in Mycobacterium smegmatis.
- Enzymatic assays to determine the substrate and product of Rv2949c.
Main Results:
- A transposon mutant deficient in p-hydroxybenzoic acid derivatives had the insertion in Rv2949c.
- Recombinant Rv2949c enzyme catalyzed the conversion of chorismate to p-hydroxybenzoate.
- Kinetic analysis revealed specific substrate affinity and catalytic efficiency for Rv2949c.
- The enzyme was identified as a chorismate pyruvate-lyase.
Conclusions:
- Rv2949c is the chorismate pyruvate-lyase responsible for the direct synthesis of p-hydroxybenzoic acid from chorismate in M. tuberculosis.
- Rv2949c is the sole enzymatic source of p-hydroxybenzoic acid, a precursor to critical virulence factors.