Structures of the Insecticidal Toxin Complex Subunit XptA2 Highlight Roles for Flexible Domains
The Toxin Complex (Tc) superfamily consists of toxin translocases that contribute to the targeting, delivery, and cytotoxicity of certain pathogenic Gram-negative bacteria. Membrane receptor targeting is driven by the A-subunit (TcA), which comprises IgG-like receptor binding domains (RBDs) at the s...
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MDPI AG
2023-08-01
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| Series: | International Journal of Molecular Sciences |
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| Online Access: | https://www.mdpi.com/1422-0067/24/17/13221 |
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| author | Cole L. Martin David W. Chester Christopher D. Radka Lurong Pan Zhengrong Yang Rachel C. Hart Elad M. Binshtein Zhao Wang Lisa Nagy Lawrence J. DeLucas Stephen G. Aller |
| author_facet | Cole L. Martin David W. Chester Christopher D. Radka Lurong Pan Zhengrong Yang Rachel C. Hart Elad M. Binshtein Zhao Wang Lisa Nagy Lawrence J. DeLucas Stephen G. Aller |
| author_sort | Cole L. Martin |
| collection | DOAJ |
| description | The Toxin Complex (Tc) superfamily consists of toxin translocases that contribute to the targeting, delivery, and cytotoxicity of certain pathogenic Gram-negative bacteria. Membrane receptor targeting is driven by the A-subunit (TcA), which comprises IgG-like receptor binding domains (RBDs) at the surface. To better understand XptA2, an insect specific TcA secreted by the symbiont <i>X. nematophilus</i> from the intestine of entomopathogenic nematodes, we determined structures by X-ray crystallography and cryo-EM. Contrary to a previous report, XptA2 is pentameric. RBD-B exhibits an indentation from crystal packing that indicates loose association with the shell and a hotspot for possible receptor binding or a trigger for conformational dynamics. A two-fragment XptA2 lacking an intact linker achieved the folded pre-pore state like wild type (wt), revealing no requirement of the linker for protein folding. The linker is disordered in all structures, and we propose it plays a role in dynamics downstream of the initial pre-pore state. |
| first_indexed | 2024-03-10T23:22:05Z |
| format | Article |
| id | doaj.art-fee46897d1844787bfb336bf918a0ca8 |
| institution | Directory Open Access Journal |
| issn | 1661-6596 1422-0067 |
| language | English |
| last_indexed | 2024-03-10T23:22:05Z |
| publishDate | 2023-08-01 |
| publisher | MDPI AG |
| record_format | Article |
| series | International Journal of Molecular Sciences |
| spelling | doaj.art-fee46897d1844787bfb336bf918a0ca82023-11-19T08:14:10ZengMDPI AGInternational Journal of Molecular Sciences1661-65961422-00672023-08-0124171322110.3390/ijms241713221Structures of the Insecticidal Toxin Complex Subunit XptA2 Highlight Roles for Flexible DomainsCole L. Martin0David W. Chester1Christopher D. Radka2Lurong Pan3Zhengrong Yang4Rachel C. Hart5Elad M. Binshtein6Zhao Wang7Lisa Nagy8Lawrence J. DeLucas9Stephen G. Aller10Department of Pharmacology & Toxicology, University of Alabama at Birmingham, Birmingham, AL 35205, USADepartment of Pharmacology & Toxicology, University of Alabama at Birmingham, Birmingham, AL 35205, USADepartment of Pharmacology & Toxicology, University of Alabama at Birmingham, Birmingham, AL 35205, USADepartment of Pharmacology & Toxicology, University of Alabama at Birmingham, Birmingham, AL 35205, USADepartment of Biochemistry & Molecular Genetics, University of Alabama at Birmingham, Birmingham, AL 35205, USADepartment of Pathology, Microbiology & Immunology, Vanderbilt University Medical Center, Nashville, TN 37232, USADepartment of Pathology, Microbiology & Immunology, Vanderbilt University Medical Center, Nashville, TN 37232, USABiochemistry & Molecular Pharmacology, Cryo-Electron Microscopy and Tomography Core, Baylor College of Medicine, Houston, TX 77030, USADepartment of Mathematics, Engineering & Physical Sciences, Jefferson State Community College, Jefferson Campus, Birmingham, AL 35215, USAPredictive Oncology Inc., 200 Riverhills Business Park, Suite 250, Birmingham, AL 35242, USADepartment of Pharmacology & Toxicology, University of Alabama at Birmingham, Birmingham, AL 35205, USAThe Toxin Complex (Tc) superfamily consists of toxin translocases that contribute to the targeting, delivery, and cytotoxicity of certain pathogenic Gram-negative bacteria. Membrane receptor targeting is driven by the A-subunit (TcA), which comprises IgG-like receptor binding domains (RBDs) at the surface. To better understand XptA2, an insect specific TcA secreted by the symbiont <i>X. nematophilus</i> from the intestine of entomopathogenic nematodes, we determined structures by X-ray crystallography and cryo-EM. Contrary to a previous report, XptA2 is pentameric. RBD-B exhibits an indentation from crystal packing that indicates loose association with the shell and a hotspot for possible receptor binding or a trigger for conformational dynamics. A two-fragment XptA2 lacking an intact linker achieved the folded pre-pore state like wild type (wt), revealing no requirement of the linker for protein folding. The linker is disordered in all structures, and we propose it plays a role in dynamics downstream of the initial pre-pore state.https://www.mdpi.com/1422-0067/24/17/13221TcAtoxin translocaseCryo-EMX-ray crystallography |
| spellingShingle | Cole L. Martin David W. Chester Christopher D. Radka Lurong Pan Zhengrong Yang Rachel C. Hart Elad M. Binshtein Zhao Wang Lisa Nagy Lawrence J. DeLucas Stephen G. Aller Structures of the Insecticidal Toxin Complex Subunit XptA2 Highlight Roles for Flexible Domains International Journal of Molecular Sciences TcA toxin translocase Cryo-EM X-ray crystallography |
| title | Structures of the Insecticidal Toxin Complex Subunit XptA2 Highlight Roles for Flexible Domains |
| title_full | Structures of the Insecticidal Toxin Complex Subunit XptA2 Highlight Roles for Flexible Domains |
| title_fullStr | Structures of the Insecticidal Toxin Complex Subunit XptA2 Highlight Roles for Flexible Domains |
| title_full_unstemmed | Structures of the Insecticidal Toxin Complex Subunit XptA2 Highlight Roles for Flexible Domains |
| title_short | Structures of the Insecticidal Toxin Complex Subunit XptA2 Highlight Roles for Flexible Domains |
| title_sort | structures of the insecticidal toxin complex subunit xpta2 highlight roles for flexible domains |
| topic | TcA toxin translocase Cryo-EM X-ray crystallography |
| url | https://www.mdpi.com/1422-0067/24/17/13221 |
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