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Mao Z, Fleming JR, Mayans O, Frey J, Schleheck D, Schink B, Müller N. AMP-dependent phosphite dehydrogenase, a phosphorylating enzyme in dissimilatory phosphite oxidation. Proc Natl Acad Sci U S A 2023; 120:e2309743120. [PMID: 37922328 PMCID: PMC10636320 DOI: 10.1073/pnas.2309743120] [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: 06/14/2023] [Accepted: 09/20/2023] [Indexed: 11/05/2023] Open
Abstract
Oxidation of phosphite (HPO32-) to phosphate (HPO42-) releases electrons at a very low redox potential (E0'= -690 mV) which renders phosphite an excellent electron donor for microbial energy metabolism. To date, two pure cultures of strictly anaerobic bacteria have been isolated that run their energy metabolism on the basis of phosphite oxidation, the Gram-negative Desulfotignum phosphitoxidans (DSM 13687) and the Gram-positive Phosphitispora fastidiosa (DSM 112739). Here, we describe the key enzyme for dissimilatory phosphite oxidation in these bacteria. The enzyme catalyzed phosphite oxidation in the presence of adenosine monophosphate (AMP) to form adenosine diphosphate (ADP), with concomitant reduction of oxidized nicotinamide adenine dinucleotide (NAD+) to reduced nicotinamide adenine dinucleotide (NADH). The enzyme of P. fastidiosa was heterologously expressed in Escherichia coli. It has a molecular mass of 35.2 kDa and a high affinity for phosphite and NAD+. Its activity was enhanced more than 100-fold by addition of ADP-consuming adenylate kinase (myokinase) to a maximal activity between 30 and 80 mU x mg protein-1. A similar NAD-dependent enzyme oxidizing phosphite to phosphate with concomitant phosphorylation of AMP to ADP is found in D. phosphitoxidans, but this enzyme could not be heterologously expressed. Based on sequence analysis, these phosphite-oxidizing enzymes are related to nucleotide-diphosphate-sugar epimerases and indeed represent AMP-dependent phosphite dehydrogenases (ApdA). A reaction mechanism is proposed for this unusual type of substrate-level phosphorylation reaction.
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Affiliation(s)
- Zhuqing Mao
- Department of Biology, University of Konstanz, Constance78457, Germany
- Konstanz Research School Chemical Biology, Departments of Chemistry and Biology, University of Konstanz, Constance78457, Germany
| | - Jennifer R. Fleming
- Department of Biology, University of Konstanz, Constance78457, Germany
- Konstanz Research School Chemical Biology, Departments of Chemistry and Biology, University of Konstanz, Constance78457, Germany
| | - Olga Mayans
- Department of Biology, University of Konstanz, Constance78457, Germany
- Konstanz Research School Chemical Biology, Departments of Chemistry and Biology, University of Konstanz, Constance78457, Germany
| | - Jasmin Frey
- Department of Biology, University of Konstanz, Constance78457, Germany
| | - David Schleheck
- Department of Biology, University of Konstanz, Constance78457, Germany
- Konstanz Research School Chemical Biology, Departments of Chemistry and Biology, University of Konstanz, Constance78457, Germany
| | - Bernhard Schink
- Department of Biology, University of Konstanz, Constance78457, Germany
- Konstanz Research School Chemical Biology, Departments of Chemistry and Biology, University of Konstanz, Constance78457, Germany
| | - Nicolai Müller
- Department of Biology, University of Konstanz, Constance78457, Germany
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Li WL, Dong X, Lu R, Zhou YL, Zheng PF, Feng D, Wang Y. Microbial ecology of sulfur cycling near the sulfate-methane transition of deep-sea cold seep sediments. Environ Microbiol 2021; 23:6844-6858. [PMID: 34622529 DOI: 10.1111/1462-2920.15796] [Citation(s) in RCA: 23] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2021] [Revised: 09/23/2021] [Accepted: 09/28/2021] [Indexed: 11/27/2022]
Abstract
Microbial sulfate reduction is largely associated with anaerobic methane oxidation and alkane degradation in sulfate-methane transition zone (SMTZ) of deep-sea cold seeps. How the sulfur cycling is mediated by microbes near SMTZ has not been fully understood. In this study, we detected a shallow SMTZ in three of eight sediment cores sampled from two cold seep areas in the South China Sea. One hundred ten genomes representing sulfur-oxidizing bacteria (SOB) and sulfur-reducing bacteria (SRB) strains were identified from three SMTZ-bearing cores. In the layers above SMTZ, SOB were mostly constituted by Campylobacterota, Gammaproteobacteria and Alphaproteobacteria that probably depended on nitrogen oxides and/or oxygen for oxidation of sulfide and thiosulfate in near-surface sediment layers. In the layers below the SMTZ, the deltaproteobacterial SRB genomes and metatranscriptomes revealed CO2 fixation by Wood-Ljungdahl pathway, sulfate reduction and nitrogen fixation for syntrophic or fermentative lifestyle. A total of 68% of the metagenome assembled genomes were not adjacent to known species in a phylogenomic tree, indicating a high diversity of bacteria involved in sulfur cycling. With the large number of genomes for SOB and SRB, our study uncovers the microbial populations that potentially mediate sulfur metabolism and associated carbon and nitrogen cycles, which sheds light on complex biogeochemical processes in deep-sea environments.
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Affiliation(s)
- Wen-Li Li
- Department of Life Science, Institute of Deep Sea Science and Engineering, Chinese Academy of Sciences, Sanya, Hainan, 572000, China
| | - Xiyang Dong
- School of Marine Sciences, Sun Yat-Sen University, Zhuhai, 519082, China.,Southern Marine Science and Engineering Guangdong Laboratory (Zhuhai), Zhuhai, 519000, China
| | - Rui Lu
- Department of Life Science, Institute of Deep Sea Science and Engineering, Chinese Academy of Sciences, Sanya, Hainan, 572000, China.,University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Ying-Li Zhou
- Department of Life Science, Institute of Deep Sea Science and Engineering, Chinese Academy of Sciences, Sanya, Hainan, 572000, China.,University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Peng-Fei Zheng
- Department of Life Science, Institute of Deep Sea Science and Engineering, Chinese Academy of Sciences, Sanya, Hainan, 572000, China
| | - Dong Feng
- Shanghai Engineering Research Center of Hadal Science and Technology, College of Marine Sciences, Shanghai Ocean University, Shanghai, 201306, China
| | - Yong Wang
- Department of Life Science, Institute of Deep Sea Science and Engineering, Chinese Academy of Sciences, Sanya, Hainan, 572000, China
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