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Juárez-Hernández EO, Casados-Vázquez LE, Brieba LG, Torres-Larios A, Jimenez-Sandoval P, Barboza-Corona JE. The crystal structure of the chitinase ChiA74 of Bacillus thuringiensis has a multidomain assembly. Sci Rep 2019; 9:2591. [PMID: 30796308 PMCID: PMC6385353 DOI: 10.1038/s41598-019-39464-z] [Citation(s) in RCA: 21] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2018] [Accepted: 01/24/2019] [Indexed: 01/04/2023] Open
Abstract
There is no structural information about any chitinase synthesized by Bacillus thuringiensis, the most successful microbial insect larvicide used worldwide. In this study, we solved the 3D structure of the chitinase ChiA74 at 2.26 Å. The crystal structure shows that ChiA74 is composed of a modular arrangement formed by (i) a catalytic region (CD), (ii) a chitinase insertion domain (CID), (iii) a fibronectin type III domain (FnIII), and (iv) a chitin binding domain (CBD). The location of the CBD with respect to the CD has no structural similarity to other chitinases with known structures. The activity of a ChiA74 lacking its secretion signal peptide (ChiA74Δsp) and a truncated version lacking its CBD/FnIII domains (ChiA74Δsp-50) did not have statistical differences in activity against colloidal chitin. However, ChiA74Δsp exhibits 4.5 and 2.0 higher activity than versions lacking the CBD (ChiA74Δsp-60) and CBD/FnIII domains (ChiA74Δsp-50), respectively, when crystalline chitin was used as substrate. Our data suggest that the CBD might plays a significant role in crystalline chitin hydrolysis. We also demonstrated the importance of the catalytic E211 in the CD, as mutants ChiA74ΔspE211N and ChiA74ΔspD207N, E211N were inactive against colloidal and crystalline chitins, chitosan and 4-MU-GlcNAc3. ChiA74 has a processive activity producing oligosaccharides with degree of polymerization (DP) of 1 (GlcNAc) and 2 (GlcNAc2).
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Affiliation(s)
- Estefania O Juárez-Hernández
- Universidad de Guanajuato Campus Irapuato-Salamanca, División de Ciencias de la Vida, Posgrado en Biociencias, Irapuato, Guanajuato, 36500, Mexico
| | - Luz E Casados-Vázquez
- Universidad de Guanajuato Campus Irapuato-Salamanca, División de Ciencias de la Vida, Posgrado en Biociencias, Irapuato, Guanajuato, 36500, Mexico.,Universidad de Guanajuato Campus Irapuato-Salamanca, División de Ciencias de la Vida, Departamento de Alimentos, Irapuato, Guanajuato, 36500, Mexico
| | - Luis G Brieba
- Laboratorio Nacional de Genómica para la Biodiversidad, Centro de Investigación y de Estudios Avanzados del Instituto Politécnico Nacional (LANGEBIO-CINVESTAV), Apartado Postal 629, Irapuato, Guanajuato, 36824, Mexico
| | - Alfredo Torres-Larios
- Departamento de Bioquímica y Biología Estructural, Instituto de Fisiología Celular, Universidad Nacional Autónoma de México, Circuito Exterior s/n, Ciudad Universitaria, Apartado Postal 70-243, Ciudad de México, 04510, Mexico
| | - Pedro Jimenez-Sandoval
- Laboratorio Nacional de Genómica para la Biodiversidad, Centro de Investigación y de Estudios Avanzados del Instituto Politécnico Nacional (LANGEBIO-CINVESTAV), Apartado Postal 629, Irapuato, Guanajuato, 36824, Mexico.
| | - José E Barboza-Corona
- Universidad de Guanajuato Campus Irapuato-Salamanca, División de Ciencias de la Vida, Posgrado en Biociencias, Irapuato, Guanajuato, 36500, Mexico. .,Universidad de Guanajuato Campus Irapuato-Salamanca, División de Ciencias de la Vida, Departamento de Alimentos, Irapuato, Guanajuato, 36500, Mexico.
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Akiba T, Okumura S. Parasporins 1 and 2: Their structure and activity. J Invertebr Pathol 2017; 142:44-49. [DOI: 10.1016/j.jip.2016.10.005] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2016] [Revised: 09/14/2016] [Accepted: 10/17/2016] [Indexed: 11/25/2022]
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Xu C, Wang BC, Yu Z, Sun M. Structural insights into Bacillus thuringiensis Cry, Cyt and parasporin toxins. Toxins (Basel) 2014; 6:2732-70. [PMID: 25229189 PMCID: PMC4179158 DOI: 10.3390/toxins6092732] [Citation(s) in RCA: 93] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2014] [Revised: 08/26/2014] [Accepted: 08/28/2014] [Indexed: 11/30/2022] Open
Abstract
Since the first X-ray structure of Cry3Aa was revealed in 1991, numerous structures of B. thuringiensis toxins have been determined and published. In recent years, functional studies on the mode of action and resistance mechanism have been proposed, which notably promoted the developments of biological insecticides and insect-resistant transgenic crops. With the exploration of known pore-forming toxins (PFTs) structures, similarities between PFTs and B. thuringiensis toxins have provided great insights into receptor binding interactions and conformational changes from water-soluble to membrane pore-forming state of B. thuringiensis toxins. This review mainly focuses on the latest discoveries of the toxin working mechanism, with the emphasis on structural related progress. Based on the structural features, B. thuringiensis Cry, Cyt and parasporin toxins could be divided into three categories: three-domain type α-PFTs, Cyt toxin type β-PFTs and aerolysin type β-PFTs. Structures from each group are elucidated and discussed in relation to the latest data, respectively.
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Affiliation(s)
- Chengchen Xu
- State Key Laboratory of Agricultural Microbiology, College of Life Science and Technology, Huazhong Agricultural University, Wuhan 430070, China.
| | - Bi-Cheng Wang
- Department of Biochemistry and Molecular Biology, University of Georgia, Athens, GA 30602, USA.
| | - Ziniu Yu
- State Key Laboratory of Agricultural Microbiology, College of Life Science and Technology, Huazhong Agricultural University, Wuhan 430070, China.
| | - Ming Sun
- State Key Laboratory of Agricultural Microbiology, College of Life Science and Technology, Huazhong Agricultural University, Wuhan 430070, China.
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