National Institutes of Health/National Heart, Lung, and Blood Institute (NIH/NHLBI)
P01HL128203
米国
引用
ジャーナル: Int J Mol Sci / 年: 2023 タイトル: Structures of the Insecticidal Toxin Complex Subunit XptA2 Highlight Roles for Flexible Domains. 著者: 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 / 要旨: 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 ...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 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.