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Role of APS reductase in biogeochemical sulfur isotope fractionation.
Sim, Min Sub; Ogata, Hideaki; Lubitz, Wolfgang; Adkins, Jess F; Sessions, Alex L; Orphan, Victoria J; McGlynn, Shawn E.
Affiliation
  • Sim MS; School of Earth and Environmental Sciences, Seoul National University, Seoul, 08826, South Korea. mssim@snu.ac.kr.
  • Ogata H; Division of Geological and Planetary Sciences, California Institute of Technology, Pasadena, CA, 91125, USA. mssim@snu.ac.kr.
  • Lubitz W; Max Planck Institute for Chemical Energy Conversion, Stiftstrasse 34-36, D-45470, Mülheim an der Ruhr, Germany.
  • Adkins JF; Institute of Low Temperature Science, Hokkaido University, Sapporo, 060-0819, Japan.
  • Sessions AL; Max Planck Institute for Chemical Energy Conversion, Stiftstrasse 34-36, D-45470, Mülheim an der Ruhr, Germany.
  • Orphan VJ; Division of Geological and Planetary Sciences, California Institute of Technology, Pasadena, CA, 91125, USA.
  • McGlynn SE; Division of Geological and Planetary Sciences, California Institute of Technology, Pasadena, CA, 91125, USA.
Nat Commun ; 10(1): 44, 2019 01 09.
Article in En | MEDLINE | ID: mdl-30626879
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.

Full text: 1 Collection: 01-internacional Database: MEDLINE Language: En Journal: Nat Commun Journal subject: BIOLOGIA / CIENCIA Year: 2019 Document type: Article Affiliation country: South Korea

Full text: 1 Collection: 01-internacional Database: MEDLINE Language: En Journal: Nat Commun Journal subject: BIOLOGIA / CIENCIA Year: 2019 Document type: Article Affiliation country: South Korea