Adams, N.B.P. orcid.org/0000-0003-3080-3448, Bisson, C., Brindley, A.A. et al. (4 more authors) (2020) The active site of magnesium chelatase. Nature Plants, 6 (12). pp. 1491-1502. ISSN 2055-026X
Abstract
The insertion of magnesium into protoporphyrin initiates the biosynthesis of chlorophyll, the pigment that underpins photosynthesis. This reaction, catalysed by the magnesium chelatase complex, couples ATP hydrolysis by a ChlID motor complex to chelation within the ChlH subunit. We probed the structure and catalytic function of ChlH using a combination of X-ray crystallography, computational modelling, mutagenesis and enzymology. Two linked domains of ChlH in an initially open conformation of ChlH bind protoporphyrin IX, and the rearrangement of several loops envelops this substrate, forming an active site cavity. This induced fit brings an essential glutamate (E660), proposed to be the key catalytic residue for magnesium insertion, into proximity with the porphyrin. A buried solvent channel adjacent to E660 connects the exterior bulk solvent to the active site, forming a possible conduit for the delivery of magnesium or abstraction of protons.
Metadata
Item Type: | Article |
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Authors/Creators: |
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Copyright, Publisher and Additional Information: | © The Author(s), under exclusive licence to Springer Nature Limited 2020. This is an author-produced version of a paper subsequently published in Nature Plants. Uploaded in accordance with the publisher's self-archiving policy. |
Keywords: | Photosynthesis; Structure determination |
Dates: |
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Institution: | The University of Sheffield |
Academic Units: | The University of Sheffield > Faculty of Science (Sheffield) > Department of Chemistry (Sheffield) The University of Sheffield > Faculty of Science (Sheffield) > School of Biosciences (Sheffield) > Department of Molecular Biology and Biotechnology (Sheffield) |
Depositing User: | Symplectic Sheffield |
Date Deposited: | 01 Dec 2020 10:19 |
Last Modified: | 02 Feb 2022 08:15 |
Status: | Published |
Publisher: | Springer Nature |
Refereed: | Yes |
Identification Number: | 10.1038/s41477-020-00806-9 |
Open Archives Initiative ID (OAI ID): | oai:eprints.whiterose.ac.uk:168606 |