| HOME | HELP | FEEDBACK | SUBSCRIPTIONS | ARCHIVE | SEARCH | TABLE OF CONTENTS |
|
|
|
|||||||
|
|||||||||
1 Institute for Biotechnology, Research Centre Juelich, D-52425 Juelich, Germany
2 School of Biosciences, The University of Birmingham, Edgbaston, Birmingham B15 2TT, UK
Correspondence
Lothar Eggeling
l.eggeling{at}fz-juelich.de
The lipid-rich Corynebacterianeae, to which Corynebacterium glutamicum and Mycobacterium species belong, produce both fatty acids and mycolic acids. Compared with most other bacteria, C. glutamicum possesses two fatty acid synthases, encoded by fasA (8907 kb; FAS-IA) and fasB (8988 kb; FAS-IB). Here, it was shown by mutational analyses that fasA is essential but fasB is not. However, in a fasA background, the fasB mutation results in a slightly reduced growth yield, L-glutamate production is increased, and comparative lipid analysis suggests that in vivo FAS-IB is active primarily to supply palmitate. Transcript quantifications revealed that the fasB transcript contributes 32 % to both fas transcripts during growth on glucose, affirmative for fasB expression, and that fasB is subordinate to fasA. The fasA transcript is downregulated by 8·3-fold during growth on acetate as compared with glucose. The lipid analyses also demonstrate that cells grown on propionate produce a number of uneven fatty acids (e.g. 15 : 0, 17 : 0, 17 : 1), which are not present in cells grown on glucose or acetate, suggesting that fatty acid synthase in vivo may also use propionyl-CoA as the priming unit in fatty acid synthesis. The fatty acid auxotrophic fasAB double mutant was used to determine the suggested incorporation of fatty acids into mycolic acids. Supplementation of this mutant with uniformly labelled [13C]oleate and analysis of isolated mycolic acids confirmed that mature mycolic acids in the mutant consist exclusively of two fused [13C]oleate molecules. In addition to an altered phospholipid profile, the fasB mutant also exhibits differences in its mycolic acid profile. Taken together, the results show that although FAS-IA is the most relevant fatty acid synthase of C. glutamicum and FAS-IB is supplementary, both synthases are necessary to produce the characteristic lipid environment of this organism.
This article has been cited by other articles:
|
|
 |
|
  A. K. Brown, A. Papaemmanouil, V. Bhowruth, A. Bhatt, L. G. Dover, and G. S. Besra Flavonoid inhibitors as novel antimycobacterial agents targeting Rv0636, a putative dehydratase enzyme involved in Mycobacterium tuberculosis fatty acid synthase II Microbiology, October 1, 2007; 153(10): 3314 - 3322. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 R. Gande, L. G. Dover, K. Krumbach, G. S. Besra, H. Sahm, T. Oikawa, and L. Eggeling The Two Carboxylases of Corynebacterium glutamicum Essential for Fatty Acid and Mycolic Acid Synthesis J. Bacteriol., July 15, 2007; 189(14): 5257 - 5264. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 C. Chalut, L. Botella, C. de Sousa-D'Auria, C. Houssin, and C. Guilhot The nonredundant roles of two 4'-phosphopantetheinyl transferases in vital processes of Mycobacteria PNAS, May 30, 2006; 103(22): 8511 - 8516. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 N. Suzuki, N. Okai, H. Nonaka, Y. Tsuge, M. Inui, and H. Yukawa High-Throughput Transposon Mutagenesis of Corynebacterium glutamicum and Construction of a Single-Gene Disruptant Mutant Library. Appl. Envir. Microbiol., May 1, 2006; 72(5): 3750 - 3755. [Abstract] [Full Text] [PDF]
|
|
| HOME | HELP | FEEDBACK | SUBSCRIPTIONS | ARCHIVE | SEARCH | TABLE OF CONTENTS |
| INT J SYST EVOL MICROBIOL | MICROBIOLOGY | J GEN VIROL |
| J MED MICROBIOL | ALL SGM JOURNALS | |
