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Sim MS, Ogata H, Lubitz W, Adkins JF, Sessions AL, Orphan VJ, McGlynn SE. Role of APS reductase in biogeochemical sulfur isotope fractionation. Nat Commun 2019; 10:44. [PMID: 30626879 PMCID: PMC6327049 DOI: 10.1038/s41467-018-07878-4] [Citation(s) in RCA: 23] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2018] [Accepted: 11/29/2018] [Indexed: 11/09/2022] Open
Abstract
Sulfur isotope fractionation resulting from microbial sulfate reduction (MSR) provides some of the earliest evidence of life, and secular variations in fractionation values reflect changes in biogeochemical cycles. Here we determine the sulfur isotope effect of the enzyme adenosine phosphosulfate reductase (Apr), which is present in all known organisms conducting MSR and catalyzes the first reductive step in the pathway and reinterpret the sedimentary sulfur isotope record over geological time. Small fractionations may be attributed to low sulfate concentrations and/or high respiration rates, whereas fractionations greater than that of Apr require a low chemical potential at that metabolic step. Since Archean sediments lack fractionation exceeding the Apr value of 20‰, they are indicative of sulfate reducers having had access to ample electron donors to drive their metabolisms. Large fractionations in post-Archean sediments are congruent with a decline of favorable electron donors as aerobic and other high potential metabolic competitors evolved.
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Affiliation(s)
- Min Sub Sim
- School of Earth and Environmental Sciences, Seoul National University, Seoul, 08826, South Korea. .,Division of Geological and Planetary Sciences, California Institute of Technology, Pasadena, CA, 91125, USA.
| | - Hideaki Ogata
- Max Planck Institute for Chemical Energy Conversion, Stiftstrasse 34-36, D-45470, Mülheim an der Ruhr, Germany.,Institute of Low Temperature Science, Hokkaido University, Sapporo, 060-0819, Japan
| | - Wolfgang Lubitz
- Max Planck Institute for Chemical Energy Conversion, Stiftstrasse 34-36, D-45470, Mülheim an der Ruhr, Germany
| | - Jess F Adkins
- Division of Geological and Planetary Sciences, California Institute of Technology, Pasadena, CA, 91125, USA
| | - Alex L Sessions
- Division of Geological and Planetary Sciences, California Institute of Technology, Pasadena, CA, 91125, USA
| | - Victoria J Orphan
- Division of Geological and Planetary Sciences, California Institute of Technology, Pasadena, CA, 91125, USA
| | - Shawn E McGlynn
- Division of Geological and Planetary Sciences, California Institute of Technology, Pasadena, CA, 91125, USA. .,Earth-Life Science Institute, Tokyo Institute of Technology, Ookayama, Tokyo, 152-8550, Japan.
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Duarte AG, Santos AA, Pereira IAC. Electron transfer between the QmoABC membrane complex and adenosine 5'-phosphosulfate reductase. BIOCHIMICA ET BIOPHYSICA ACTA-BIOENERGETICS 2016; 1857:380-6. [PMID: 26768116 DOI: 10.1016/j.bbabio.2016.01.001] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/16/2015] [Revised: 12/30/2015] [Accepted: 01/04/2016] [Indexed: 10/22/2022]
Abstract
The dissimilatory adenosine 5'-phosphosulfate reductase (AprAB) is a key enzyme in the sulfate reduction pathway that catalyzes the reversible two electron reduction of adenosine 5'-phosphosulfate (APS) to sulfite and adenosine monophosphate (AMP). The physiological electron donor for AprAB is proposed to be the QmoABC membrane complex, coupling the quinone-pool to sulfate reduction. However, direct electron transfer between these two proteins has never been observed. In this work we demonstrate for the first time direct electron transfer between the Desulfovibrio desulfuricans ATCC 27774 QmoABC complex and AprAB. Cyclic voltammetry conducted with the modified Qmo electrode and AprAB in the electrolyte solution presented the Qmo electrochemical signature with two additional well-defined one electron redox processes, attributed to the AprAB FAD redox behavior. Moreover, experiments performed under catalytic conditions using the QmoABC modified electrode, with AprAB and APS in solution, show a catalytic current peak develop in the cathodic wave, attributed to substrate reduction, and which is not observed in the absence of QmoABC. Substrate dependence conducted with different electrode preparations (with and without immobilized Qmo) demonstrated that the QmoABC complex is essential for efficient electron delivery to AprAB, in order to sustain catalysis. These results confirm the role of Qmo in electron transfer to AprAB.
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Affiliation(s)
- Américo G Duarte
- Instituto de Tecnologia Química e Biológica António Xavier, Universidade Nova de Lisboa, Av. da República, Estação Agronómica Nacional, 2780-157, Oeiras, Portugal.
| | - André A Santos
- Instituto de Tecnologia Química e Biológica António Xavier, Universidade Nova de Lisboa, Av. da República, Estação Agronómica Nacional, 2780-157, Oeiras, Portugal
| | - Inês A C Pereira
- Instituto de Tecnologia Química e Biológica António Xavier, Universidade Nova de Lisboa, Av. da República, Estação Agronómica Nacional, 2780-157, Oeiras, Portugal.
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