ArticleBiochemistry2012
MacA is a second cytochrome c peroxidase of Geobacter sulfurreducens.
Article in Biochemistry, 2012. The graph could read no effect estimate from its abstract, so it casts no vote on the map. Cited by 17 papers.
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Who cites it
17 citing papers in PubMed, 47 citations in OpenAlex.
- Overview of pathways and dynamic interactions of c-type cytochromes in Geobacter sulfurreducens.Biochemical Society transactions · 2026Review
- Synthesis and biophysical characterization of bioengineered cytochrome nanowires.European biophysics journal : EBJ · 2026Article
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- Exploring oxidative stress pathways inFrontiers in microbiology · 2023Article
- AlphaFold2 fails to predict protein fold switching.Protein science : a publication of the Protein Society · 2022Article
- Competitive advantage of oxygen-tolerant bioanodes ofBiofilm · 2021Article
- Isolation and Polyphasic Characterization ofMicroorganisms · 2021Article
- Cytochromes in Extracellular Electron Transfer inApplied and environmental microbiology · 2021Review
- Divergent Nrf Family Proteins and MtrCAB Homologs Facilitate Extracellular Electron Transfer in Aeromonas hydrophila.Applied and environmental microbiology · 2018Article
- Article
- Identification of Different Putative Outer Membrane Electron Conduits Necessary for Fe(III) Citrate, Fe(III) Oxide, Mn(IV) Oxide, or Electrode Reduction by Geobacter sulfurreducens.Journal of bacteriology · 2018Article
- Nutrient and acetate amendment leads to acetoclastic methane production and microbial community change in a non-producing Australian coal well.Microbial biotechnology · 2018Article
- Oxidation triggers extensive conjugation and unusual stabilization of two di-heme dication diradical intermediates: role of bridging group for electronic communication.Chemical science · 2016Article
- Abundance of the multiheme c-type cytochrome OmcB increases in outer biofilm layers of electrode-grown Geobacter sulfurreducens.PloS one · 2014Article
- Structure of the processive rubber oxygenase RoxA from Xanthomonas sp.Proceedings of the National Academy of Sciences of the United States of America · 2013Article
- Impact of quaternary structure upon bacterial cytochrome c peroxidases: does homodimerization matter?Biochemistry · 2012Article
- Multi-heme proteins: nature's electronic multi-purpose tool.Biochimica et biophysica actaReview
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Authors and funding
8 authors at 2 institutions in 2 countries.
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Abstract
The metal-reducing δ-proteobacterium Geobacter sulfurreducens produces a large number of c-type cytochromes, many of which have been implicated in the transfer of electrons to insoluble metal oxides. Among these, the dihemic MacA was assigned a central role. Here we have produced G. sulfurreducens MacA by recombinant expression in Escherichia coli and have solved its three-dimensional structure in three different oxidation states. Sequence comparisons group MacA into the family of diheme cytochrome c peroxidases, and the protein indeed showed hydrogen peroxide reductase activity with ABTS(-2) as an electron donor. The observed K(M) was 38.5 ± 3.7 μM H(2)O(2) and v(max) was 0.78 ± 0.03 μmol of H(2)O(2)·min(-1)·mg(-1), resulting in a turnover number k(cat) = 0.46 · s(-1). In contrast, no Fe(III) reductase activity was observed. MacA was found to display electrochemical properties similar to other bacterial diheme peroxidases, in addition to the ability to electrochemically mediate electron transfer to the soluble cytochrome PpcA. Differences in activity between CcpA and MacA can be rationalized with structural variations in one of the three loop regions, loop 2, that undergoes conformational changes during reductive activation of the enzyme. This loop is adjacent to the active site heme and forms an open loop structure rather than a more rigid helix as in CcpA. For the activation of the protein, the loop has to displace the distal ligand to the active site heme, H93, in loop 1. A H93G variant showed an unexpected formation of a helix in loop 2 and disorder in loop 1, while a M297H variant that altered the properties of the electron transfer heme abolished reductive activation.
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