Role of APS reductase in biogeochemical sulfur isotope fractionation
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.
Additional Information
© 2018 The Author(s). This article is licensed under a Creative Commons Attribution 4.0 International License, which permits use, sharing, adaptation, distribution and reproduction in any medium or format, as long as you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons license, and indicate if changes were made. The images or other third party material in this article are included in the article's Creative Commons license, unless indicated otherwise in a credit line to the material. If material is not included in the article's Creative Commons license and your intended use is not permitted by statutory regulation or exceeds the permitted use, you will need to obtain permission directly from the copyright holder. To view a copy of this license, visit http://creativecommons.org/licenses/by/4.0/. Received 29 June 2018; Accepted 29 November 2018; Published 09 January 2019. Data availability: Data supporting the findings of this study are available within the paper and in the supplementary information file or are available from the corresponding author upon reasonable request. This work was supported by the Research Resettlement Fund for the new faculty of Seoul National University to M.S.S., the NASA Research Opportunities in Space and Earth Sciences grant award number NNX14AO48G to S.E.M. and V.J.O., JSPS KAKENHI Grant Number 10751084 to S.E.M., and the Gordon and Betty Moore Foundation Grant GBMF 3306 to V.J.O. and A.L.S. This research was a part of the project titled 'Understanding the deepsea biosphere on seafloor hydrothermal vents in the Indian Ridge (20170411)', funded by the Ministry of Oceans and Fisheries, Korea. We are grateful for insightful and helpful conversations with Boswell A. Wing, David T. Johnston, David A. Fike, and Itay Halevy. We are especially grateful to Tatsuhiko Yagi and Yoshiki Higuchi for helping with initiating collaboration. Contributions: M.S.S. and S.E.M. devised the study. H.O. and W.L. purified APS reductase, and M.S.S. executed enzymatic assay and sulfur isotope measurements. M.S.S. and S.E.M. wrote the first draft of the manuscript, and J.F.A., A.L.S., and V.J.O. contributed to interpretation and writing. The authors declare no competing interests.Attached Files
Published - s41467-018-07878-4.pdf
Supplemental Material - 41467_2018_7878_MOESM1_ESM.pdf
Supplemental Material - 41467_2018_7878_MOESM2_ESM.docx
Supplemental Material - 41467_2018_7878_MOESM3_ESM.xlsx
Supplemental Material - 41467_2018_7878_MOESM4_ESM.xlsx
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Additional details
- PMCID
- PMC6327049
- Eprint ID
- 92242
- Resolver ID
- CaltechAUTHORS:20190114-083925177
- Seoul National University
- NNX14AO48G
- NASA
- 10751084
- Japan Society for the Promotion of Science (JSPS)
- GBMF 3306
- Gordon and Betty Moore Foundation
- 20170411
- Ministry of Oceans and Fisheries (Korea)
- Created
-
2019-01-14Created from EPrint's datestamp field
- Updated
-
2023-05-23Created from EPrint's last_modified field
- Caltech groups
- Division of Geological and Planetary Sciences