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Martin CL, Chester DW, Radka CD, Pan L, Yang Z, Hart RC, Binshtein EM, Wang Z, Nagy L, DeLucas LJ, Aller SG. Structures of the Insecticidal Toxin Complex Subunit XptA2 Highlight Roles for Flexible Domains. Int J Mol Sci 2023; 24:13221. [PMID: 37686027 PMCID: PMC10487846 DOI: 10.3390/ijms241713221] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2023] [Revised: 08/18/2023] [Accepted: 08/20/2023] [Indexed: 09/10/2023] Open
Abstract
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 X. nematophilus 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.
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Affiliation(s)
- Cole L. Martin
- Department of Pharmacology & Toxicology, University of Alabama at Birmingham, Birmingham, AL 35205, USA; (C.L.M.); (D.W.C.); (C.D.R.); (L.P.)
| | - David W. Chester
- Department of Pharmacology & Toxicology, University of Alabama at Birmingham, Birmingham, AL 35205, USA; (C.L.M.); (D.W.C.); (C.D.R.); (L.P.)
| | - Christopher D. Radka
- Department of Pharmacology & Toxicology, University of Alabama at Birmingham, Birmingham, AL 35205, USA; (C.L.M.); (D.W.C.); (C.D.R.); (L.P.)
- Department of Microbiology, Immunology, and Molecular Genetics, University of Kentucky, Lexington, KY 40536, USA
| | - Lurong Pan
- Department of Pharmacology & Toxicology, University of Alabama at Birmingham, Birmingham, AL 35205, USA; (C.L.M.); (D.W.C.); (C.D.R.); (L.P.)
| | - Zhengrong Yang
- Department of Biochemistry & Molecular Genetics, University of Alabama at Birmingham, Birmingham, AL 35205, USA;
| | - Rachel C. Hart
- Department of Pathology, Microbiology & Immunology, Vanderbilt University Medical Center, Nashville, TN 37232, USA; (R.C.H.); (E.M.B.)
| | - Elad M. Binshtein
- Department of Pathology, Microbiology & Immunology, Vanderbilt University Medical Center, Nashville, TN 37232, USA; (R.C.H.); (E.M.B.)
| | - Zhao Wang
- Biochemistry & Molecular Pharmacology, Cryo-Electron Microscopy and Tomography Core, Baylor College of Medicine, Houston, TX 77030, USA;
| | - Lisa Nagy
- Department of Mathematics, Engineering & Physical Sciences, Jefferson State Community College, Jefferson Campus, Birmingham, AL 35215, USA;
| | - Lawrence J. DeLucas
- Predictive Oncology Inc., 200 Riverhills Business Park, Suite 250, Birmingham, AL 35242, USA;
| | - Stephen G. Aller
- Department of Pharmacology & Toxicology, University of Alabama at Birmingham, Birmingham, AL 35205, USA; (C.L.M.); (D.W.C.); (C.D.R.); (L.P.)
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High-level over-expression, purification, and crystallization of a novel phospholipase C/sphingomyelinase from Pseudomonas aeruginosa. Protein Expr Purif 2012. [PMID: 23201280 PMCID: PMC3601568 DOI: 10.1016/j.pep.2012.11.005] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
The hemolytic phospholipase C/sphingomyelinase PlcH from the
opportunistic pathogen Pseudomonas aeruginosa represents the
founding member of a growing family of virulence factors identified in a wide range of
bacterial and fungal pathogens. In P. aeruginosa PlcH is
co-expressed with a 17 kDa chaperone (PlcR2) and secreted as a fully
folded heterodimer (PlcHR2) of approximately 95 kDa, by the twin
arginine translocase (TAT) via the cytoplasmic membrane and through the outer membrane, by
the Xcp (TypeII) secretory system. PlcHR2 has been shown to be an important virulence
factor in model P. aeruginosa infections and is selectively
cytotoxic, at picomolar concentrations to mammalian endothelial cells. Here we report how
the various challenges starting from protein overexpression in the native organism
P. aeruginosa, the use of detergents in the crystallization and
data collection using the most advanced μ-focus synchrotron beam lines were overcome.
Native diffraction data of this heterodimeric protein complex were collected up to a
resolution of 4 Å, whereas needle-shaped crystals of
l-selenomethionine substituted PlcHR2 with a maximum
diameter of 10 micron were used to collect data sets with a maximum resolution of
2.75 Å.
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Sugiki T, Ichikawa O, Miyazawa-Onami M, Shimada I, Takahashi H. Isotopic labeling of heterologous proteins in the yeast Pichia pastoris and Kluyveromyces lactis. Methods Mol Biol 2012; 831:19-36. [PMID: 22167666 DOI: 10.1007/978-1-61779-480-3_2] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Several protein expression systems are available for the preparation of stable isotope-labeled recombinant proteins for NMR studies. Yeast expression systems have several advantages over prokaryotic systems, such as the widely used Escherichia coli expression system. Protein expression using the methylotrophic yeast Pichia pastoris is commonly employed for the preparation of isotope-labeled proteins. Recently, the hemiascomycete yeast Kluyveromyces lactis expression system was reported as being useful for preparing proteins for NMR studies. Since each yeast expression system has different features, their applications have increased in number. In this chapter, we describe procedures for the efficient production of uniformly isotope-labeled proteins using the P. pastoris and the K. lactis yeast expression systems.
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