Structural and functional insights into the first Bacillus thuringiensis vegetative insecticidal protein of the Vpb4 fold, active against western corn rootworm.

Autor: Jean-Louis Kouadio, Meiying Zheng, Michael Aikins, David Duda, Stephen Duff, Danqi Chen, Jun Zhang, Jason Milligan, Christina Taylor, Patricia Mamanella, Timothy Rydel, Colton Kessenich, Timothy Panosian, Yong Yin, William Moar, Kara Giddings, Yoonseong Park, Agoston Jerga, Jeffrey Haas
Jazyk: angličtina
Rok vydání: 2021
Předmět:
Zdroj: PLoS ONE, Vol 16, Iss 12, p e0260532 (2021)
Druh dokumentu: article
ISSN: 1932-6203
DOI: 10.1371/journal.pone.0260532
Popis: The western corn rootworm (WCR), Diabrotica virgifera virgifera LeConte, is a major maize pest in the United States causing significant economic loss. The emergence of field-evolved resistant WCR to Bacillus thuringiensis (Bt) traits has prompted the need to discover and deploy new insecticidal proteins in transgenic maize. In the current study we determined the crystal structure and mode of action (MOA) of the Vpb4Da2 protein (formerly known as Vip4Da2) from Bt, the first identified insecticidal Vpb4 protein with commercial level control against WCR. The Vpb4Da2 structure exhibits a six-domain architecture mainly comprised of antiparallel β-sheets organized into β-sandwich layers. The amino-terminal domains 1-3 of the protein share structural homology with the protective antigen (PA) PA14 domain and encompass a long β-pore forming loop as in the clostridial binary-toxB module. Domains 5 and 6 at the carboxyl-terminal half of Vpb4Da2 are unique as this extension is not observed in PA or any other structurally-related protein other than Vpb4 homologs. These unique Vpb4 domains adopt the topologies of carbohydrate-binding modules known to participate in receptor-recognition. Functional assessment of Vpb4Da2 suggests that domains 4-6 comprise the WCR receptor binding region and are key in conferring the observed insecticidal activity against WCR. The current structural analysis was complemented by in vitro and in vivo characterizations, including immuno-histochemistry, demonstrating that Vpb4Da2 follows a MOA that is consistent with well-characterized 3-domain Bt insecticidal proteins despite significant structural differences.
Databáze: Directory of Open Access Journals
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