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ARS Home » Northeast Area » Frederick, Maryland » Foreign Disease-Weed Science Research » Research » Publications at this Location » Publication #386587

Research Project: Molecular Identification, Characterization, and Biology of Foreign and Emerging Viral and Bacterial Plant Pathogens

Location: Foreign Disease-Weed Science Research

Title: Critical residues for proteolysis activity of maize chlorotic dwarf virus (MCDV) 3C-like protease and comparison of activity of orthologous waikavirus proteases

item Stewart, Lucy
item Willman, Matthew
item Marty, Deemarie - Dee
item COLE, ANNA - College Of Wooster
item Willie, Kristen

Submitted to: Virology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 12/21/2021
Publication Date: 2/2/2022
Citation: Stewart, L.R., Willman, M.R., Marty, D., Cole, A., Willie, K.J. 2022. Critical residues for proteolysis activity of maize chlorotic dwarf virus (MCDV) 3C-like protease and comparison of activity of orthologous waikavirus proteases. Virology. 567:57-64.

Interpretive Summary: Many viruses infecting plants and animals utilize a polyprotein expression strategy in which a single large polyprotein is encoded by the virus and cleaved by one or more viral proteases into mature protein products. One group of proteases is the 3C-like virus protease found in a wide spectrum of viruses including the corn virus maize chlorotic dwarf virus, which belongs to a group of plant-infecting waikaviruses. To better understand the 3C-like protease of MCDV and waikaviruses, protease activity was compared for a set of targeted mutants of the MCDV protease, and of divergent homologs from other waikavirus strains and species. Together, the data demonstrate the importance of the conserved catalytic residues, and of a tyrosine residue conserved in the waikavirus proteases, Y2774 in MCDV-S. This finding informs the activity and potential structure of this group virus proteases that are crucial for virus maturation, improving our understanding of these proteases and providing potential targets for applications to disrupt virus maturation.

Technical Abstract: Maize chlorotic dwarf virus (MCDV) encodes a 3C-like protease that cleaves the N-terminal polyprotein (R78) as previously demonstrated. Here, we examined amino acid residues required for catalytic activity of the protease, including those in the predicted catalytic triad, amino acid residues H2667, D2704, and C2798, as well as H2817 hypothesized to be important in substrate binding. These and other residues were targeted for mutagenesis and tested for proteolytic cleavage activity on the N-terminal 78 kDa MCDV-S polyprotein substrate to identify mutants that abolished catalytic activity. Mutations that altered the predicted catalytic triad residues and H2817 abolished MCDV-S protease activity, as did mutagenesis of a conserved tyrosine residue, Y2774. The protease activity and R78 cleavage of orthologs from divergent MCDV isolates MCDV-Tn and MCDV-M1, and other waikavirus species including rice tungro spherical virus (RTSV) and bellflower vein chlorosis virus (BVCV) were also examined