Activity of Cytosolic Ascorbate Peroxidase (APX) from Panicum virgatum against Ascorbate and Phenylpropanoids

Zhang, Bixia; Lewis, Jacob A.; Kovacs, Frank; Sattler, Scott E.; Sarath, Gautam; Kang, ChulHee

doi:10.3390/ijms24021778

Open AccessArticle

Activity of Cytosolic Ascorbate Peroxidase (APX) from Panicum virgatum against Ascorbate and Phenylpropanoids

by

Bixia Zhang

¹

,

Jacob A. Lewis

¹

,

Frank Kovacs

²

,

Scott E. Sattler

³

,

Gautam Sarath

³

and

ChulHee Kang

^1,*

¹

Department of Chemistry, Washington State University, Pullman, WA 99164, USA

²

Chemistry Department, University of Nebraska-Kearney, Kearney, NE 68849, USA

³

Wheat, Sorghum and Forage Research Unit, U.S. Department of Agriculture—Agricultural Research Service, Lincoln, NE 68583, USA

^*

Author to whom correspondence should be addressed.

Int. J. Mol. Sci. 2023, 24(2), 1778; https://doi.org/10.3390/ijms24021778

Submission received: 20 December 2022 / Revised: 10 January 2023 / Accepted: 12 January 2023 / Published: 16 January 2023

(This article belongs to the Section Biochemistry)

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Abstract

APX is a key antioxidant enzyme in higher plants, scavenging H₂O₂ with ascorbate in several cellular compartments. Here, we report the crystal structures of cytosolic ascorbate peroxidase from switchgrass (Panicum virgatum L., Pvi), 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 H₂O₂-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.

Keywords: ascorbate; switchgrass; ROS; stress; phenylpropanoids; ascorbate peroxidase; lignification; X-ray crystallography; oxidation

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MDPI and ACS Style

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. 2023, 24, 1778. https://doi.org/10.3390/ijms24021778

AMA Style

Zhang B, Lewis JA, Kovacs F, Sattler SE, Sarath G, Kang C. Activity of Cytosolic Ascorbate Peroxidase (APX) from Panicum virgatum against Ascorbate and Phenylpropanoids. International Journal of Molecular Sciences. 2023; 24(2):1778. https://doi.org/10.3390/ijms24021778

Chicago/Turabian Style

Zhang, Bixia, Jacob A. Lewis, Frank Kovacs, Scott E. Sattler, Gautam Sarath, and ChulHee Kang. 2023. "Activity of Cytosolic Ascorbate Peroxidase (APX) from Panicum virgatum against Ascorbate and Phenylpropanoids" International Journal of Molecular Sciences 24, no. 2: 1778. https://doi.org/10.3390/ijms24021778

APA Style

Zhang, B., Lewis, J. A., Kovacs, F., Sattler, S. E., Sarath, G., & Kang, C. (2023). Activity of Cytosolic Ascorbate Peroxidase (APX) from Panicum virgatum against Ascorbate and Phenylpropanoids. International Journal of Molecular Sciences, 24(2), 1778. https://doi.org/10.3390/ijms24021778

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Activity of Cytosolic Ascorbate Peroxidase (APX) from Panicum virgatum against Ascorbate and Phenylpropanoids

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