Pyrophosphate-Dependent ATP Formation from Acetyl Coenzyme A in Syntrophus aciditrophicus, a New Twist on ATP Formation
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- Department of Microbiology and Plant Biology, University of Oklahoma, Norman, Oklahoma, USA
- Department of Biological Chemistry, University of California Los Angeles, Los Angeles, California, USA
- Department of Chemistry and Biochemistry, University of California Los Angeles, Los Angeles, California, USA
- Department of Microbiology, Immunology and Molecular Genetics, University of California Los Angeles, Los Angeles, California, USA
- Department of Chemistry and Biochemistry, University of California Los Angeles, Los Angeles, California, USA, Department of Biological Chemistry, University of California Los Angeles, Los Angeles, California, USA
- Chemical Sciences Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee, USA
- Aging and Metabolism Research Program, Oklahoma Medical Research Foundation, Oklahoma City, Oklahoma, USA
Syntrophus aciditrophicus is a model syntrophic bacterium that degrades key intermediates in anaerobic decomposition, such as benzoate, cyclohexane-1-carboxylate, and certain fatty acids, to acetate when grown with hydrogen-/formate-consuming microorganisms. ATP formation coupled to acetate production is the main source for energy conservation by S. aciditrophicus. However, the absence of homologs for phosphate acetyltransferase and acetate kinase in the genome of S. aciditrophicus leaves it unclear as to how ATP is formed, as most fermentative bacteria rely on these two enzymes to synthesize ATP from acetyl coenzyme A (CoA) and phosphate. Here, we combine transcriptomic, proteomic, metabolite, and enzymatic approaches to show that S. aciditrophicus uses AMP-forming, acetyl-CoA synthetase (Acs1) for ATP synthesis from acetyl-CoA. acs1 mRNA and Acs1 were abundant in transcriptomes and proteomes, respectively, of S. aciditrophicus grown in pure culture and coculture. Cell extracts of S. aciditrophicus had low or undetectable acetate kinase and phosphate acetyltransferase activities but had high acetyl-CoA synthetase activity under all growth conditions tested. Both Acs1 purified from S. aciditrophicus and recombinantly produced Acs1 catalyzed ATP and acetate formation from acetyl-CoA, AMP, and pyrophosphate. High pyrophosphate levels and a high AMP-to-ATP ratio (5.9 ± 1.4) in S. aciditrophicus cells support the operation of Acs1 in the acetate-forming direction. Thus, S. aciditrophicus has a unique approach to conserve energy involving pyrophosphate, AMP, acetyl-CoA, and an AMP-forming, acetyl-CoA synthetase.
- Research Organization:
- Oak Ridge National Laboratory (ORNL), Oak Ridge, TN (United States); Univ. of Oklahoma, Norman, OK (United States)
- Sponsoring Organization:
- USDOE Office of Science (SC), Basic Energy Sciences (BES). Chemical Sciences, Geosciences, and Biosciences Division; USDOE Office of Science (SC), Biological and Environmental Research (BER); National Institutes of Health (NIH)
- Grant/Contract Number:
- FG02-96ER20214; AC05-00OR22725; FC02-02ER63421; R01GM085402; FC02-02ER6342; FG02-08ER64689
- OSTI ID:
- 1784812
- Alternate ID(s):
- OSTI ID: 1324038; OSTI ID: 1604787
- Journal Information:
- mBio, Journal Name: mBio Vol. 7 Journal Issue: 4; ISSN 2161-2129
- Publisher:
- American Society for MicrobiologyCopyright Statement
- Country of Publication:
- United States
- Language:
- English
Web of Science
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