Plant peroxidases: substrate complexes with mechanistic implications.
Plant peroxidases are capable of binding phenolic substrates, and it has been possible to crystallize complexes between horseradish peroxidase C (HRP C) and benzhydroxamic acid. The X-ray structures of the binary HRP C:ferulic acid complex and the ternary HRP C:CN(-):ferulic acid complex to 2.0 and 1.45 A resolution, respectively, have also been solved recently. Ferulic acid is a naturally occurring phenolic compound found in the plant cell wall and it is an in vivo substrate for plant peroxidases. The X-ray structures demonstrate the flexibility of the aromatic-donor-binding site in plant peroxidases and highlight the role of the distal arginine in substrate oxidation and ligand binding. A general mechanism of peroxidase substrate oxidation (compound I-->compound II and compound II-->resting state) can be proposed on the basis of the complexes and a large body of biochemical evidence.
Gajhede
M
M
Protein Structure Group, Department of Chemistry, University of Copenhagen, Universitetsparken 5, DK2100, Denmark. gajhede@psg.ki.ku.dk
D001665:Binding Sites; D002384:Catalysis; D003373:Coumaric Acids / Q000737:chemistry / Q000378:metabolism; D018360:Crystallography, X-Ray; D006735:Horseradish Peroxidase / Q000737:chemistry* / Q000378:metabolism*; D006877:Hydroxamic Acids / Q000737:chemistry / Q000378:metabolism; D010084:Oxidation-Reduction; D010944:Plants / Q000201:enzymology*; D017434:Protein Structure, Tertiary
D003373:Coumaric Acids; D006877:Hydroxamic Acids; C004999:ferulic acid; D006735:Horseradish Peroxidase; C006696:benzohydroxamic acid