1. Crystal structures of cyanobacterial light-dependent protochlorophyllide oxidoreductase
- Author
-
Chen-Song Dong, Lin Liu, Min Zhang, Wei-Lun Zhang, Xiao Wang, Yu-Shuai Li, and Qiao Wang
- Subjects
0301 basic medicine ,Cyanobacteria ,Chlorophyll ,Models, Molecular ,Rossmann fold ,Oxidoreductases Acting on CH-CH Group Donors ,Light ,Stereochemistry ,Protein Conformation ,Thermosynechococcus ,Dehydrogenase ,Crystal structure ,Crystallography, X-Ray ,Catalysis ,03 medical and health sciences ,Protochlorophyllide ,Oxidoreductase ,Chlorophyll biosynthesis ,chemistry.chemical_classification ,Multidisciplinary ,030102 biochemistry & molecular biology ,biology ,Chemistry ,Synechocystis ,Biological Sciences ,biology.organism_classification ,030104 developmental biology ,NAD+ kinase ,Protons ,NADP - Abstract
The reduction of protochlorophyllide (Pchlide) to chlorophyllide (Chlide) is the penultimate step of chlorophyll biosynthesis. In oxygenic photosynthetic bacteria, algae, and plants, this reaction can be catalyzed by the light-dependent Pchlide oxidoreductase (LPOR), a member of the short-chain dehydrogenase superfamily sharing a conserved Rossmann fold for NAD(P)H binding and the catalytic activity. Whereas modeling and simulation approaches have been used to study the catalytic mechanism of this light-driven reaction, key details of the LPOR structure remain unclear. We determined the crystal structures of LPOR from two cyanobacteria, Synechocystis sp. PCC 6803 and Thermosynechococcus elongatus . Structural analysis defines the LPOR core fold, outlines the LPOR–NADPH interaction network, identifies the residues forming the substrate cavity and the proton-relay path, and reveals the role of the LPOR-specific loop. These findings provide a basis for understanding the structure-function relationships of the light-driven Pchlide reduction.
- Published
- 2020