@article{115c02f4ae964e7f8c6e6f9ab79a16a6,
title = "The active site of magnesium chelatase",
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.",
author = "Adams, {Nathan B.P.} and Claudine Bisson and Brindley, {Amanda A.} and Farmer, {David A.} and Davison, {Paul A.} and Reid, {James D.} and Hunter, {C. Neil}",
note = "Funding Information: We thank Diamond Light Source for beamtime (proposals mx8987 and 12788) and the staff of beamlines i24, i02, i03 and i04 for technical support. We thank D. Ladakis, R. W. Pickersgill, D. G. Brown and M. J. Warren for the provision of structural data on the truncation of the CobN protein. N.B.P.A., C.B., A.A.B., P.A.D., J.D.R. and C.N.H. acknowledge financial support from the Biotechnology and Biological Sciences Research Council (BBSRC UK) (award no. BB/M000265/1). C.B. was also supported by core funding from the Department of Molecular Biology and Biotechnology, University of Sheffield. C.N.H was also supported by Synergy Award no. 854126 from the European Research Council. D.A.F. was supported by a BBSRC White Rose Doctoral Training Program (award no. BB/M011151/1). Publisher Copyright: {\textcopyright} 2020, The Author(s), under exclusive licence to Springer Nature Limited.",
year = "2020",
month = dec,
doi = "10.1038/s41477-020-00806-9",
language = "English",
volume = "6",
pages = "1491--1502",
journal = "Nature Plants",
issn = "2055-0278",
publisher = "Nature Research",
number = "12",
}