6YSG
Magnesium chelatase H subunit (ChlH) from Synechocystis sp.PCC6803 to 2.54 A resolution
Summary for 6YSG
| Entry DOI | 10.2210/pdb6ysg/pdb |
| Related | 6YS9 |
| Descriptor | Mg-chelatase subunit ChlH, CITRIC ACID (3 entities in total) |
| Functional Keywords | magnesium chelatase, chlorophyll, photosynthesis |
| Biological source | Synechocystis sp. PCC 6803 substr. Kazusa |
| Total number of polymer chains | 2 |
| Total formula weight | 301935.12 |
| Authors | Bisson, C.,Hunter, C.N. (deposition date: 2020-04-22, release date: 2020-12-09, Last modification date: 2024-01-24) |
| Primary citation | Adams, N.B.P.,Bisson, C.,Brindley, A.A.,Farmer, D.A.,Davison, P.A.,Reid, J.D.,Hunter, C.N. The active site of magnesium chelatase. Nat.Plants, 6:1491-1502, 2020 Cited by PubMed 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. PubMed: 33257858DOI: 10.1038/s41477-020-00806-9 PDB entries with the same primary citation |
| Experimental method | X-RAY DIFFRACTION (2.54 Å) |
Structure validation
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