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Bannantine JP, Duffy SC, Colombatti Olivieri MA, Behr MA, Biet F, Price NPJ. Genetic and chemical control of tuberculostearic acid production in Mycobacterium avium subspecies paratuberculosis. Microbiol Spectr 2024; 12:e0050824. [PMID: 38501867 PMCID: PMC11064506 DOI: 10.1128/spectrum.00508-24] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2024] [Accepted: 02/28/2024] [Indexed: 03/20/2024] Open
Abstract
Tuberculostearic acid (TBSA) is a fatty acid unique to mycobacteria and some corynebacteria and has been studied due to its diagnostic value, biofuel properties, and role in membrane dynamics. In this study, we demonstrate that TBSA production can be abrogated either by addition of pivalic acid to mycobacterial growth cultures or by a bfaA gene knockout encoding a flavin adenine dinucleotide (FAD)-binding oxidoreductase. Mycobacterium avium subspecies paratuberculosis (Map) growth and TBSA production were inhibited in 0.5-mg/mL pivalic acid-supplemented cultures, but higher concentrations were needed to have a similar effect in other mycobacteria, including Mycobacterium smegmatis. While Map C-type strains, isolated from cattle and other ruminants, will produce TBSA in the absence of pivalic acid, the S-type Map strains, typically isolated from sheep, do not produce TBSA in any condition. A SAM-dependent methyltransferase encoded by bfaB and FAD-binding oxidoreductase are both required in the two-step biosynthesis of TBSA. However, S-type strains contain a single-nucleotide polymorphism in the bfaA gene, rendering the oxidoreductase enzyme vestigial. This results in the production of an intermediate, termed 10-methylene stearate, which is detected only in S-type strains. Fatty acid methyl ester analysis of a C-type Map bfaA knockout revealed the loss of TBSA production, but the intermediate was present, similar to the S-type strains. Collectively, these results demonstrate the subtle biochemical differences between two primary genetic lineages of Map and other mycobacteria as well as explain the resulting phenotype at the genetic level. These data also suggest that TBSA should not be used as a diagnostic marker for Map.IMPORTANCEBranched-chain fatty acids are a predominant cell wall component among species belonging to the Mycobacterium genus. One of these is TBSA, which is a long-chain middle-branched fatty acid used as a diagnostic marker for Mycobacterium tuberculosis. This fatty acid is also an excellent biolubricant. Control of its production is important for industrial purposes as well as understanding the biology of mycobacteria. In this study, we discovered that a carboxylic acid compound termed pivalic acid inhibits TBSA production in mycobacteria. Furthermore, Map strains from two separate genetic lineages (C-type and S-type) showed differential production of TBSA. Cattle-type strains of Mycobacterium avium subspecies paratuberculosis produce TBSA, while the sheep-type strains do not. This important phenotypic difference is attributed to a single-nucleotide deletion in sheep-type strains of Map. This work sheds further light on the mechanism used by mycobacteria to produce tuberculostearic acid.
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Affiliation(s)
- John P. Bannantine
- National Animal Disease Center, USDA Agricultural Research Service, Ames, Iowa, USA
| | - Shannon C. Duffy
- Department of Microbiology and Immunology, McGill University, Montreal, Quebec, Canada
| | - María A. Colombatti Olivieri
- National Animal Disease Center, USDA Agricultural Research Service, Ames, Iowa, USA
- ARS Participation Program, Oak Ridge Institute for Science and Education (ORISE), Oak Ridge, Tennessee, USA
| | - Marcel A. Behr
- Department of Microbiology and Immunology, McGill University, Montreal, Quebec, Canada
| | - Franck Biet
- INRAE, ISP, Université de Tours, Nouzilly, France
| | - Neil P. J. Price
- National Center for Agricultural Utilization Research, USDA Agricultural Research Service, Peoria, Illinois, USA
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Blitzblau HG, Consiglio AL, Teixeira P, Crabtree DV, Chen S, Konzock O, Chifamba G, Su A, Kamineni A, MacEwen K, Hamilton M, Tsakraklides V, Nielsen J, Siewers V, Shaw AJ. Production of 10-methyl branched fatty acids in yeast. BIOTECHNOLOGY FOR BIOFUELS 2021; 14:12. [PMID: 33413611 PMCID: PMC7791843 DOI: 10.1186/s13068-020-01863-0] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 10/25/2020] [Accepted: 12/17/2020] [Indexed: 06/12/2023]
Abstract
BACKGROUND Despite the environmental value of biobased lubricants, they account for less than 2% of global lubricant use due to poor thermo-oxidative stability arising from the presence of unsaturated double bonds. Methyl branched fatty acids (BFAs), particularly those with branching near the acyl-chain mid-point, are a high-performance alternative to existing vegetable oils because of their low melting temperature and full saturation. RESULTS We cloned and characterized two pathways to produce 10-methyl BFAs isolated from actinomycetes and γ-proteobacteria. In the two-step bfa pathway of actinomycetes, BfaB methylates Δ9 unsaturated fatty acids to form 10-methylene BFAs, and subsequently, BfaA reduces the double bond to produce a fully saturated 10-methyl branched fatty acid. A BfaA-B fusion enzyme increased the conversion efficiency of 10-methyl BFAs. The ten-methyl palmitate production (tmp) pathway of γ-proteobacteria produces a 10-methylene intermediate, but the TmpA putative reductase was not active in E. coli or yeast. Comparison of BfaB and TmpB activities revealed a range of substrate specificities from C14-C20 fatty acids unsaturated at the Δ9, Δ10 or Δ11 position. We demonstrated efficient production of 10-methylene and 10-methyl BFAs in S. cerevisiae by secretion of free fatty acids and in Y. lipolytica as triacylglycerides, which accumulated to levels more than 35% of total cellular fatty acids. CONCLUSIONS We report here the characterization of a set of enzymes that can produce position-specific methylene and methyl branched fatty acids. Yeast expression of bfa enzymes can provide a platform for the large-scale production of branched fatty acids suitable for industrial and consumer applications.
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Affiliation(s)
- Hannah G Blitzblau
- Novogy, Inc., 85 Bolton Street, Cambridge, MA, 02140, USA.
- Ginkgo BioWorks, 27 Drydock Ave., Boston, MA, 02210, USA.
| | - Andrew L Consiglio
- Novogy, Inc., 85 Bolton Street, Cambridge, MA, 02140, USA
- Ginkgo BioWorks, 27 Drydock Ave., Boston, MA, 02210, USA
| | - Paulo Teixeira
- Department of Biology and Biological Engineering, Chalmers University of Technology, Kemivägen 10, 41296, Gothenburg, Sweden
| | | | - Shuyan Chen
- Novogy, Inc., 85 Bolton Street, Cambridge, MA, 02140, USA
- Ginkgo BioWorks, 27 Drydock Ave., Boston, MA, 02210, USA
| | - Oliver Konzock
- Department of Biology and Biological Engineering, Chalmers University of Technology, Kemivägen 10, 41296, Gothenburg, Sweden
| | - Gamuchirai Chifamba
- Novogy, Inc., 85 Bolton Street, Cambridge, MA, 02140, USA
- Ginkgo BioWorks, 27 Drydock Ave., Boston, MA, 02210, USA
| | - Austin Su
- Novogy, Inc., 85 Bolton Street, Cambridge, MA, 02140, USA
| | - Annapurna Kamineni
- Novogy, Inc., 85 Bolton Street, Cambridge, MA, 02140, USA
- Ginkgo BioWorks, 27 Drydock Ave., Boston, MA, 02210, USA
| | - Kyle MacEwen
- Novogy, Inc., 85 Bolton Street, Cambridge, MA, 02140, USA
- Ginkgo BioWorks, 27 Drydock Ave., Boston, MA, 02210, USA
| | - Maureen Hamilton
- Novogy, Inc., 85 Bolton Street, Cambridge, MA, 02140, USA
- Ginkgo BioWorks, 27 Drydock Ave., Boston, MA, 02210, USA
| | - Vasiliki Tsakraklides
- Novogy, Inc., 85 Bolton Street, Cambridge, MA, 02140, USA
- Ginkgo BioWorks, 27 Drydock Ave., Boston, MA, 02210, USA
| | - Jens Nielsen
- Department of Biology and Biological Engineering, Chalmers University of Technology, Kemivägen 10, 41296, Gothenburg, Sweden
- Novo Nordisk Foundation Center for Biosustainability, Chalmers University of Technology, Kemivägen 10, 41296, Gothenburg, Sweden
- BioInnovation Institute, Ole Maaløes Vej 3, 2200, Copenhagen N, Denmark
| | - Verena Siewers
- Department of Biology and Biological Engineering, Chalmers University of Technology, Kemivägen 10, 41296, Gothenburg, Sweden
- Novo Nordisk Foundation Center for Biosustainability, Chalmers University of Technology, Kemivägen 10, 41296, Gothenburg, Sweden
| | - A Joe Shaw
- Novogy, Inc., 85 Bolton Street, Cambridge, MA, 02140, USA
- Manus Biosynthesis, 1030 Massachusetts Ave. #300, Cambridge, MA, 02138, USA
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Abstract
It has been known for several decades that cyclopropane fatty acids (CFAs) occur in the phospholipids of many species of bacteria. CFAs are formed by the addition of a methylene group, derived from the methyl group of S-adenosylmethionine, across the carbon-carbon double bond of unsaturated fatty acids (UFAs). The C1 transfer does not involve free fatty acids or intermediates of phospholipid biosynthesis but, rather, mature phospholipid molecules already incorporated into membrane bilayers. Furthermore, CFAs are typically produced at the onset of the stationary phase in bacterial cultures. CFA formation can thus be considered a conditional, postsynthetic modification of bacterial membrane lipid bilayers. This modification is noteworthy in several respects. It is catalyzed by a soluble enzyme, although one of the substrates, the UFA double bond, is normally sequestered deep within the hydrophobic interior of the phospholipid bilayer. The enzyme, CFA synthase, discriminates between phospholipid vesicles containing only saturated fatty acids and those containing UFAs; it exhibits no affinity for vesicles of the former composition. These and other properties imply that topologically novel protein-lipid interactions occur in the biosynthesis of CFAs. The timing and extent of the UFA-to-CFA conversion in batch cultures and the widespread distribution of CFA synthesis among bacteria would seem to suggest an important physiological role for this phenomenon, yet its rationale remains unclear despite experimental tests of a variety of hypotheses. Manipulation of the CFA synthase of Escherichia coli by genetic methods has nevertheless provided valuable insight into the physiology of CFA formation. It has identified the CFA synthase gene as one of several rpoS-regulated genes of E. coli and has provided for the construction of strains in which proposed cellular functions of CFAs can be properly evaluated. Cloning and manipulation of the CFA synthase structural gene have also enabled this novel but extremely unstable enzyme to be purified and analyzed in molecular terms and have led to the identification of mechanistically related enzymes in clinically important bacterial pathogens.
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Affiliation(s)
- D W Grogan
- Department of Biological Sciences, University of Cincinnati, Ohio 45221-0006, USA
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