8FF7

Cytosolic ascorbate peroxidase mutant from Panicum virgatum- ascorbate complex

Summary for 8FF7

• Entry DOI: 10.2210/pdb8ff7/pdb
• Descriptor: Cytosolic ascorbate peroxidase, ASCORBIC ACID, PROTOPORPHYRIN IX CONTAINING FE, ... (5 entities in total)
• Functional Keywords: ascorbate peroxidase, ascorbate, heme, hydrogen peroxide, switchgrass, oxidoreductase
• Biological source: Panicum virgatum (switchgrass)
• Total number of polymer chains: 6
• Total formula weight: 168704.38

Authors

Zhang, B.,Kang, C. (deposition date: 2022-12-07, release date: 2023-02-01, Last modification date: 2023-10-25)

Primary citation

Zhang, B.,Lewis, J.A.,Kovacs, F.,Sattler, S.E.,Sarath, G.,Kang, C.
Activity of Cytosolic Ascorbate Peroxidase (APX) from Panicum virgatum against Ascorbate and Phenylpropanoids.
Int J Mol Sci, 24:-, 2023

PubMed Abstract: APX is a key antioxidant enzyme in higher plants, scavenging HO with ascorbate in several cellular compartments. Here, we report the crystal structures of cytosolic ascorbate peroxidase from switchgrass ( L., ), a strategic feedstock plant with several end uses. The overall structure of PviAPX was similar to the structures of other APX family members, with a bound ascorbate molecule at the ɣ-heme edge pocket as in other APXs. Our results indicated that the HO-dependent oxidation of ascorbate displayed positive cooperativity. Significantly, our study suggested that PviAPX can oxidize a broad range of phenylpropanoids with δ-meso site in a rather similar efficiency, which reflects its role in the fortification of cell walls in response to insect feeding. Based on detailed structural and kinetic analyses and molecular docking, as well as that of closely related APX enzymes, the critical residues in each substrate-binding site of PviAPX are proposed. Taken together, these observations shed new light on the function and catalysis of PviAPX, and potentially benefit efforts improve plant health and biomass quality in bioenergy and forage crops.

PubMed: 36675291
DOI: 10.3390/ijms24021778

Experimental method

X-RAY DIFFRACTION (2.194 Å)