A Combinatorial Approach to Biochemical Space: Description and Application to the Redox Distribution of Metabolism
Name
Bains-2012-A Combinatorial Approach to Biochemical Space.pdf
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485.74 KB
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Author(s)
Bains, William
Seager, Sara
Date Issued
March 2012
Journal
Astrobiology
Publisher
Mary Ann Liebert, Inc.
Citation
Bains, William, and Sara Seager. “A Combinatorial Approach to Biochemical Space: Description and Application to the Redox Distribution of Metabolism.” Astrobiology 12.3 (2012): 271–281. Web.
Version
Final published version
Abstract
Redox chemistry is central to life on Earth. It is well known that life uses redox chemistry to capture energy from environmental chemical energy gradients. Here, we propose that a second use of redox chemistry, related to building biomass from environmental carbon, is equally important to life. We apply a method based on chemical structure to evaluate the redox range of different groups of terrestrial biochemicals, and find that they are consistently of intermediate redox range. We hypothesize the common intermediate range is related to the chemical space required for the selection of a consistent set of metabolites. We apply a computational method to show that the redox range of the chemical space shows the same restricted redox range as the biochemicals that are selected from that space. By contrast, the carbon from which life is composed is available in the environment only as fully oxidized or reduced species. We therefore argue that redox chemistry is essential to life for assembling biochemicals for biomass building. This biomass-building reason for life to require redox chemistry is in addition (and in contrast) to life's use of redox chemistry to capture energy. Life's use of redox chemistry for biomass capture will generate chemical by-products—that is, biosignature gases—that are not in redox equilibrium with life's environment. These potential biosignature gases may differ from energy-capture redox biosignatures. Key Words: Metabolism—Modeling studies—Redox—Biosignatures. Astrobiology 12, 271–281.
MIT Department
Massachusetts Institute of Technology. Department of Earth, Atmospheric, and Planetary Sciences
Massachusetts Institute of Technology. Department of Physics
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Article is made available in accordance with the publisher's policy and may be subject to US copyright law. Please refer to the publisher's site for terms of use.
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DOI of Published Version
https://doi.org/10.1089/ast.2011.0718
