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Interrogating the function of a putative carbon monoxide oxidase in Caulobacter crescentus (769.17)
Author(s) -
Larkin Isaac,
Crosson Sean,
Colman Albert
Publication year - 2014
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.28.1_supplement.769.17
Subject(s) - caulobacter crescentus , carbon monoxide , bacteria , chemistry , carbon fibers , escherichia coli , energy source , biochemistry , oxidase test , gene , food science , biology , enzyme , catalysis , genetics , bacterial protein , materials science , organic chemistry , coal , composite number , composite material
Aerobic carbon monoxide oxidase (COX) is an oxygen‐stable enzyme that enables some bacteria to use carbon monoxide as an energy and a carbon source (1), and has the potential to contribute to the conversion of syngas, the mixture of CO, H2 and CO2 that is the product of organic waste gasification, into useful organic carbon (2). However, bacteria with COX genes tend to be extremophiles or grow slowly (Td >3 h), and thus are not ideal vehicles for biotechnological innovation (3, 4). We investigated whether CCNA_00021 (21) and 00022 (22), two genes in the fast growing and genetically tractable bacterium C. crescentus, code for a functional carbon monoxide oxidase (COX). We analyzed transcriptional data from C. crescentus to determine that 21 and 22 are upregulated during carbon starvation. To determine whether C. crescentus can consume CO as an energy or carbon source, we performed growth curves of wild type C. crescentus in rich (PYE) and Glucose Exhaustion Media in gas‐tight vessels containing different mixtures of air and CO, and then used gas chromatography to analyze the evolution of the vessels’ headspace gas. Our results indicate that while C. crescentus is more tolerant of CO than E. coli, it does not consume CO while growing in either PYE or Glucose Exhaustion Media. We therefore conclude that CCNA_00021 and 00022, though structurally similar to a COX, have a different function.