title: Characterization of Class III Peroxidases from Switchgrass.
abstract: Class III peroxidases (CIIIPRX) catalyze the oxidation of monolignols, generate radicals, and ultimately lead to the formation of lignin. In general, CIIIPRX genes encode a large number of isozymes with ranges of in vitro substrate specificities. In order to elucidate the mode of substrate specificity of these enzymes, we characterized one of the CIIIPRXs (PviPRX9) from switchgrass (Panicum virgatum), a strategic plant for second-generation biofuels. The crystal structure, kinetic experiments, molecular docking, as well as expression patterns of PviPRX9 across multiple tissues and treatments, along with its levels of coexpression with the majority of genes in the monolignol biosynthesis pathway, revealed the function of PviPRX9 in lignification. Significantly, our study suggested that PviPRX9 has the ability to oxidize a broad range of phenylpropanoids with rather similar efficiencies, which reflects its role in the fortification of cell walls during normal growth and root development and in response to insect feeding. Based on the observed interactions of phenylpropanoids in the active site and analysis of kinetics, a catalytic mechanism involving two water molecules and residues histidine-42, arginine-38, and serine-71 was proposed. In addition, proline-138 and gluntamine-140 at the137P-X-P-X140motif, leucine-66, proline-67, and asparagine-176 may account for the broad substrate specificity of PviPRX9. Taken together, these observations shed new light on the function and catalysis of PviPRX9 and potentially benefit efforts to improve biomass conservation properties in bioenergy and forage crops.
authors.affiliation: Department of Chemistry (T.W.M., K.M.L., C.B., J.P.J., C.K.) and Department of Entomology (F.Z.), Washington State University, Pullman, Washington 99164.|Wheat, Sorghum, and Forage Research Unit, Agricultural Research Service, United States Department of Agriculture, Lincoln, Nebraska 68583 (N.A.P., G.S., S.E.S.).|Department of Agronomy and Horticulture, University of Nebraska, Lincoln, Nebraska 68583 (N.A.P., G.S., S.E.S.); and.|Stored Product Insect and Engineering Research Unit, United States Department of Agriculture-Agricultural Research Service Center for Grain and Animal Health, Manhattan, Kansas 66502 (E.D.S.).
authors.forename: Timothy W
authors.initials: TW
authors.lastname: Moural
authors.affiliation: Department of Chemistry (T.W.M., K.M.L., C.B., J.P.J., C.K.) and Department of Entomology (F.Z.), Washington State University, Pullman, Washington 99164.|Wheat, Sorghum, and Forage Research Unit, Agricultural Research Service, United States Department of Agriculture, Lincoln, Nebraska 68583 (N.A.P., G.S., S.E.S.).|Department of Agronomy and Horticulture, University of Nebraska, Lincoln, Nebraska 68583 (N.A.P., G.S., S.E.S.); and.|Stored Product Insect and Engineering Research Unit, United States Department of Agriculture-Agricultural Research Service Center for Grain and Animal Health, Manhattan, Kansas 66502 (E.D.S.).
authors.forename: Kevin M
authors.initials: KM
authors.lastname: Lewis
authors.affiliation: Department of Chemistry (T.W.M., K.M.L., C.B., J.P.J., C.K.) and Department of Entomology (F.Z.), Washington State University, Pullman, Washington 99164.|Wheat, Sorghum, and Forage Research Unit, Agricultural Research Service, United States Department of Agriculture, Lincoln, Nebraska 68583 (N.A.P., G.S., S.E.S.).|Department of Agronomy and Horticulture, University of Nebraska, Lincoln, Nebraska 68583 (N.A.P., G.S., S.E.S.); and.|Stored Product Insect and Engineering Research Unit, United States Department of Agriculture-Agricultural Research Service Center for Grain and Animal Health, Manhattan, Kansas 66502 (E.D.S.).
authors.forename: Carlo
authors.initials: C
authors.lastname: Barnaba
authors.affiliation: Department of Chemistry (T.W.M., K.M.L., C.B., J.P.J., C.K.) and Department of Entomology (F.Z.), Washington State University, Pullman, Washington 99164.|Wheat, Sorghum, and Forage Research Unit, Agricultural Research Service, United States Department of Agriculture, Lincoln, Nebraska 68583 (N.A.P., G.S., S.E.S.).|Department of Agronomy and Horticulture, University of Nebraska, Lincoln, Nebraska 68583 (N.A.P., G.S., S.E.S.); and.|Stored Product Insect and Engineering Research Unit, United States Department of Agriculture-Agricultural Research Service Center for Grain and Animal Health, Manhattan, Kansas 66502 (E.D.S.).
authors.forename: Fang
authors.initials: F
authors.lastname: Zhu
authors.affiliation: Department of Chemistry (T.W.M., K.M.L., C.B., J.P.J., C.K.) and Department of Entomology (F.Z.), Washington State University, Pullman, Washington 99164.|Wheat, Sorghum, and Forage Research Unit, Agricultural Research Service, United States Department of Agriculture, Lincoln, Nebraska 68583 (N.A.P., G.S., S.E.S.).|Department of Agronomy and Horticulture, University of Nebraska, Lincoln, Nebraska 68583 (N.A.P., G.S., S.E.S.); and.|Stored Product Insect and Engineering Research Unit, United States Department of Agriculture-Agricultural Research Service Center for Grain and Animal Health, Manhattan, Kansas 66502 (E.D.S.).
authors.forename: Nathan A
authors.initials: NA
authors.lastname: Palmer
authors.affiliation: Department of Chemistry (T.W.M., K.M.L., C.B., J.P.J., C.K.) and Department of Entomology (F.Z.), Washington State University, Pullman, Washington 99164.|Wheat, Sorghum, and Forage Research Unit, Agricultural Research Service, United States Department of Agriculture, Lincoln, Nebraska 68583 (N.A.P., G.S., S.E.S.).|Department of Agronomy and Horticulture, University of Nebraska, Lincoln, Nebraska 68583 (N.A.P., G.S., S.E.S.); and.|Stored Product Insect and Engineering Research Unit, United States Department of Agriculture-Agricultural Research Service Center for Grain and Animal Health, Manhattan, Kansas 66502 (E.D.S.).
authors.forename: Gautam
authors.initials: G
authors.lastname: Sarath
authors.affiliation: Department of Chemistry (T.W.M., K.M.L., C.B., J.P.J., C.K.) and Department of Entomology (F.Z.), Washington State University, Pullman, Washington 99164.|Wheat, Sorghum, and Forage Research Unit, Agricultural Research Service, United States Department of Agriculture, Lincoln, Nebraska 68583 (N.A.P., G.S., S.E.S.).|Department of Agronomy and Horticulture, University of Nebraska, Lincoln, Nebraska 68583 (N.A.P., G.S., S.E.S.); and.|Stored Product Insect and Engineering Research Unit, United States Department of Agriculture-Agricultural Research Service Center for Grain and Animal Health, Manhattan, Kansas 66502 (E.D.S.).
authors.forename: Erin D
authors.initials: ED
authors.lastname: Scully
authors.affiliation: Department of Chemistry (T.W.M., K.M.L., C.B., J.P.J., C.K.) and Department of Entomology (F.Z.), Washington State University, Pullman, Washington 99164.|Wheat, Sorghum, and Forage Research Unit, Agricultural Research Service, United States Department of Agriculture, Lincoln, Nebraska 68583 (N.A.P., G.S., S.E.S.).|Department of Agronomy and Horticulture, University of Nebraska, Lincoln, Nebraska 68583 (N.A.P., G.S., S.E.S.); and.|Stored Product Insect and Engineering Research Unit, United States Department of Agriculture-Agricultural Research Service Center for Grain and Animal Health, Manhattan, Kansas 66502 (E.D.S.).
authors.forename: Jeffrey P
authors.initials: JP
authors.lastname: Jones
authors.affiliation: Department of Chemistry (T.W.M., K.M.L., C.B., J.P.J., C.K.) and Department of Entomology (F.Z.), Washington State University, Pullman, Washington 99164.|Wheat, Sorghum, and Forage Research Unit, Agricultural Research Service, United States Department of Agriculture, Lincoln, Nebraska 68583 (N.A.P., G.S., S.E.S.).|Department of Agronomy and Horticulture, University of Nebraska, Lincoln, Nebraska 68583 (N.A.P., G.S., S.E.S.); and.|Stored Product Insect and Engineering Research Unit, United States Department of Agriculture-Agricultural Research Service Center for Grain and Animal Health, Manhattan, Kansas 66502 (E.D.S.).
authors.forename: Scott E
authors.identifier: 0000-0002-6814-4073
authors.initials: SE
authors.lastname: Sattler
authors.affiliation: Department of Chemistry (T.W.M., K.M.L., C.B., J.P.J., C.K.) and Department of Entomology (F.Z.), Washington State University, Pullman, Washington 99164; chkang@wsu.edu.|Wheat, Sorghum, and Forage Research Unit, Agricultural Research Service, United States Department of Agriculture, Lincoln, Nebraska 68583 (N.A.P., G.S., S.E.S.); chkang@wsu.edu.|Department of Agronomy and Horticulture, University of Nebraska, Lincoln, Nebraska 68583 (N.A.P., G.S., S.E.S.); and chkang@wsu.edu.|Stored Product Insect and Engineering Research Unit, United States Department of Agriculture-Agricultural Research Service Center for Grain and Animal Health, Manhattan, Kansas 66502 (E.D.S.) chkang@wsu.edu.
authors.forename: ChulHee
authors.identifier: 0000-0002-0693-7860
authors.initials: C
authors.lastname: Kang
mesh_terms: D000595:Amino Acid Sequence; D001665:Binding Sites; D055162:Biocatalysis; D002118:Calcium / Q000378:metabolism; D018360:Crystallography, X-Ray; D057075:Enzyme Assays; D018506:Gene Expression Regulation, Plant; D018745:Genome, Plant; D006418:Heme / Q000378:metabolism; D006861:Hydrogen Peroxide / Q000378:metabolism; D007700:Kinetics; D016013:Likelihood Functions; D055442:Metabolome; D062105:Molecular Docking Simulation; D008897:Panicum / Q000201:enzymology* / Q000235:genetics; D010544:Peroxidases / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism*; D017433:Protein Structure, Secondary; D055672:Static Electricity; D013379:Substrate Specificity
chemical_list: D006418:Heme; D006861:Hydrogen Peroxide; D010544:Peroxidases; D002118:Calcium