title: Crystal structure of Cry6Aa: A novel nematicidal ClyA-type α-pore-forming toxin from Bacillus thuringiensis.
abstract: Crystal (Cry) proteins from Bacillus thuringiensis (Bt) are globally used in agriculture as proteinaceous insecticides. Numerous crystal structures have been determined, and most exhibit conserved three-dimensional architectures. Recently, we have identified a novel nematicidal mechanism by which Cry6Aa triggers cell death through a necrosis-signaling pathway via an interaction with the host protease ASP-1. However, we found little sequence conservation of Cry6Aa in our functional study. Here, we report the 1.90 angstrom (Å) resolution structure of the proteolytic form of Cry6Aa (1-396), determined by X-ray crystallography. The structure of Cry6Aa is highly similar to those of the pathogenic toxin family of ClyA-type α-pore-forming toxins (α-PFTs), which are characterized by a bipartite structure comprising a head domain and a tail domain, thus suggesting that Cry6Aa exhibits a previously undescribed nematicidal mode of action. This structure also provides a framework for the functional study of other nematicidal toxins.
authors.affiliation: College of Life Science and Technology, Huazhong Agricultural University, Wuhan 430070, China.
authors.forename: Jinbo
authors.initials: J
authors.lastname: Huang
authors.affiliation: National Key Laboratory of Crop Genetic Improvement, Huazhong Agricultural University, Wuhan 430070, China.
authors.forename: Zeyuan
authors.initials: Z
authors.lastname: Guan
authors.affiliation: College of Life Science and Technology, Huazhong Agricultural University, Wuhan 430070, China; State Key Laboratory of Agricultural Microbiology, Huazhong Agricultural University, Wuhan 430070, China.
authors.forename: Liting
authors.initials: L
authors.lastname: Wan
authors.affiliation: College of Life Science and Technology, Huazhong Agricultural University, Wuhan 430070, China.
authors.forename: Tingting
authors.initials: T
authors.lastname: Zou
authors.affiliation: College of Life Science and Technology, Huazhong Agricultural University, Wuhan 430070, China; State Key Laboratory of Agricultural Microbiology, Huazhong Agricultural University, Wuhan 430070, China. Electronic address: m98sun@mail.hzau.edu.cn.
authors.forename: Ming
authors.initials: M
authors.lastname: Sun
mesh_terms: D000595:Amino Acid Sequence; D000969:Antinematodal Agents / Q000737:chemistry*; D001413:Bacillus thuringiensis / Q000378:metabolism*; D000083722:Bacillus thuringiensis Toxins; D001426:Bacterial Proteins / Q000648:ultrastructure*; D001665:Binding Sites; D004731:Endotoxins; D006460:Hemolysin Proteins / Q000648:ultrastructure*; D008969:Molecular Sequence Data; D052899:Pore Forming Cytotoxic Proteins / Q000648:ultrastructure*; D016062:Porosity; D011485:Protein Binding; D011487:Protein Conformation
chemical_list: D000969:Antinematodal Agents; D000083722:Bacillus thuringiensis Toxins; D001426:Bacterial Proteins; D004731:Endotoxins; D006460:Hemolysin Proteins; D052899:Pore Forming Cytotoxic Proteins; C030956:insecticidal crystal protein, Bacillus Thuringiensis; C087744:ApxI toxin, Bacteria
keywords: Bacillus thuringiensis; Crystal structure; Nematicidal; Pore-forming toxin