Hobbs, C., Reid, J.D. orcid.org/0000-0003-4921-1047 and Shepherd, M. (2017) The coproporphyrin ferrochelatase of Staphylococcus aureus : mechanistic insights into a regulatory iron binding site. Biochemical Journal , 474 (20). pp. 3513-3522. ISSN 0264-6021
Abstract
The majority of characterised ferrochelatase enzymes catalyse the final step of classical haem synthesis, inserting ferrous iron into protoporphyrin IX. However, for the recently-discovered coproporphyrin-dependent pathway, ferrochelatase catalyses the penultimate reaction where ferrous iron is inserted into coproporphyrin III. Ferrochelatase enzymes from the bacterial phyla Firmicutes and Actinobacteria have previously been shown to insert iron into coproporphyrin, and those from Bacillus subtilis and Staphylococcus aureus are known to be inhibited by elevated iron concentrations. The work herein reports a Km (coproporphyrin III) for S. aureus ferrochelatase of 1.5 µM and it is shown that elevating the iron concentration increases the Km for coproporphyrin III, providing a potential explanation for the observed iron-mediated substrate inhibition. Together, structural modelling, site-directed mutagenesis, and kinetic analyses confirm residue Glu271 as being essential for the binding of iron to the inhibitory regulatory site on S. aureus ferrochelatase, providing a molecular explanation for the observed substrate inhibition patterns. This work therefore has implications for how haem biosynthesis in S. aureus is regulated by iron availability.
Metadata
Item Type: | Article |
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Authors/Creators: |
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Copyright, Publisher and Additional Information: | ©2017 The Author(s). This is an author produced version of a paper subsequently published in Biochemical Journal. Uploaded in accordance with the publisher's self-archiving policy. |
Keywords: | Coproporphyrinogen; ferrochelatase; haem biosynthesis |
Dates: |
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Institution: | The University of Sheffield |
Academic Units: | The University of Sheffield > Faculty of Science (Sheffield) > Department of Chemistry (Sheffield) |
Depositing User: | Symplectic Sheffield |
Date Deposited: | 14 Sep 2017 12:51 |
Last Modified: | 01 Sep 2018 00:39 |
Published Version: | https://doi.org/10.1042/BCJ20170362 |
Status: | Published |
Publisher: | Portland Press |
Refereed: | Yes |
Identification Number: | 10.1042/BCJ20170362 |
Related URLs: | |
Open Archives Initiative ID (OAI ID): | oai:eprints.whiterose.ac.uk:120822 |