The biosynthesis of mycolic acids in Mycobacterium tuberculosis relies on multiple specialized elongation complexes interconnected by specific protein-protein interactions.
Tuberculosis kills about two million people every year and remains one of the leading causes of mortality worldwide. As a result of the increasing antibiotic resistance of Mycobacterium tuberculosis (Mtb) strains, there is an urgent need for new antitubercular drugs. Several efficient antibiotics, including isoniazid, specifically target the fatty acid synthase-II (FAS-II) complex of mycolic acid biosynthesis. We have previously shown that there are protein-protein interactions between the components of FAS-II that are essential for mycobacterial survival. We have now looked at the potential partners of FAS-II, mtFabD, the methyltransferases MmaAs, and Pks13. A combination of yeast two-hybrid and co-immunoprecipitation experiments showed that mtFabD interacts with each beta-ketoacyl-synthase (KasA, KasB and mtFabH) and with the core of FAS-II (InhA and MabA). The methyltransferases have a greater affinity for KasA and KasB than for mtFabH, suggesting that modifications on the meromycolic chains may occur during their elongation. Finally, Pks13, which catalyzes the final Claisen condensation of mycolic acids, interacts specifically with KasB. These data allowed us to determine the architecture of the multiple specialized FAS-II complexes, giving us insights into the organization of the complete mycolic acids biosynthesis. Our studies suggest a new and crucial interaction (KasB-Pks13) as a putative target for peptidomimetic antibiotics.
Veyron-Churlet
Romain
R
Département Mécanismes Moléculaires des Infections Mycobactériennes, Institut de Pharmacologie et de Biologie Structurale, Centre National de la Recherche Scientifique, 205 route de Narbonne, 31077 Toulouse Cedex 04, France.
Bigot
Sarah
S
Guerrini
Olivier
O
Verdoux
Sébastien
S
Malaga
Wladimir
W
Daffé
Mamadou
M
Zerbib
Didier
D
D015099:3-Oxoacyl-(Acyl-Carrier-Protein) Synthase / Q000378:metabolism; D000123:Acetyltransferases / Q000378:metabolism*; D001426:Bacterial Proteins / Q000378:metabolism; D054889:Fatty Acid Synthase, Type II; D047468:Immunoprecipitation; D008780:Methyltransferases / Q000378:metabolism; D024101:Mitochondrial Proteins / Q000378:metabolism; D009097:Multienzyme Complexes / Q000378:metabolism*; D009169:Mycobacterium tuberculosis / Q000201:enzymology*; D009171:Mycolic Acids / Q000378:metabolism*; D048630:Polyketide Synthases / Q000378:metabolism; D011485:Protein Binding; D025941:Protein Interaction Mapping; D020798:Two-Hybrid System Techniques
D001426:Bacterial Proteins; D024101:Mitochondrial Proteins; D009097:Multienzyme Complexes; D009171:Mycolic Acids; D048630:Polyketide Synthases; D008780:Methyltransferases; D000123:Acetyltransferases; C444656:KasB protein, Mycobacterium tuberculosis; D015099:3-Oxoacyl-(Acyl-Carrier-Protein) Synthase; D054889:Fatty Acid Synthase, Type II