title: Characterization of Mycobacterium smegmatis expressing the Mycobacterium tuberculosis fatty acid synthase I (fas1) gene.
abstract: Unlike most other bacteria, mycobacteria make fatty acids with the multidomain enzyme eukaryote-like fatty acid synthase I (FASI). Previous studies have demonstrated that the tuberculosis drug pyrazinamide and 5-chloro-pyrazinamide target FASI activity. Biochemical studies have revealed that in addition to C(16:0), Mycobacterium tuberculosis FASI synthesizes C(26:0) fatty acid, while the Mycobacterium smegmatis enzyme makes C(24:0) fatty acid. In order to express M. tuberculosis FASI in a rapidly growing Mycobacterium and to characterize the M. tuberculosis FASI in vivo, we constructed an M. smegmatis Deltafas1 strain which contained the M. tuberculosis fas1 homologue. The M. smegmatis Deltafas1 (attB::M. tuberculosis fas1) strain grew more slowly than the parental M. smegmatis strain and was more susceptible to 5-chloro-pyrazinamide. Surprisingly, while the M. smegmatis Deltafas1 (attB::M. tuberculosis fas1) strain produced C(26:0), it predominantly produced C(24:0). These results suggest that the fatty acid elongation that produces C(24:0) or C(26:0) in vivo is due to a complex interaction among FASI, FabH, and FASII and possibly other systems and is not solely due to FASI elongation, as previously suggested by in vitro studies.
authors.affiliation: Unit for Infectious Diseases, Kaplan Medical Center, The School of Medicine, Hebrew University, and Hadassah, Jerusalem, Israel. Oren_z@clalit.org.il
authors.forename: Oren
authors.initials: O
authors.lastname: Zimhony
authors.forename: Catherine
authors.initials: C
authors.lastname: Vilchèze
authors.forename: William R
authors.initials: WR
authors.lastname: Jacobs
mesh_terms: D001426:Bacterial Proteins / Q000235:genetics*; D001483:Base Sequence; D064429:Fatty Acid Synthases / Q000235:genetics*; D005227:Fatty Acids / Q000096:biosynthesis*; D008826:Microbial Sensitivity Tests; D008969:Molecular Sequence Data; D020102:Mycobacterium smegmatis / Q000187:drug effects / Q000235:genetics / Q000378:metabolism*; D009169:Mycobacterium tuberculosis / Q000187:drug effects / Q000201:enzymology*; D011718:Pyrazinamide / Q000031:analogs & derivatives* / Q000494:pharmacology
chemical_list: C111084:5-chloropyrazinamide; D001426:Bacterial Proteins; D005227:Fatty Acids; D011718:Pyrazinamide; D064429:Fatty Acid Synthases; C413881:fatty acid synthase I, mycobacteria