Cork-in-bottle occlusion of fluoride ion channels by crystallization chaperones
| Autor: | McIlwain, BC, Newstead, S, Stockbridge, RB |
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| Jazyk: | angličtina |
| Rok vydání: | 2018 |
| Předmět: |
Models
Molecular Protein Conformation alpha-Helical Binding Sites Ion Transport crystallization chaperone Amino Acid Motifs Genetic Vectors Gene Expression monobody Crystallography X-Ray Bordetella pertussis Ion Channels Recombinant Proteins Article Fluorides Bacterial Proteins ion channel Escherichia coli Protein Interaction Domains and Motifs Cloning Molecular Molecular Chaperones Protein Binding |
| Zdroj: | Structure(London, England:1993) |
| Popis: | Summary Crystallization of dual-topology fluoride (Fluc) channels requires small, soluble crystallization chaperones known as monobodies, which act as primary crystal lattice contacts. Previous structures of Flucs have been solved in the presence of monobodies that inhibit fluoride currents in single-channel electrophysiological recordings. These structures have revealed two-fold symmetric, doubly bound arrangements, with one monobody on each side of the membrane. The combined electrophysiological and structural observations raise the possibility that chaperone binding allosterically closes the channel, altering the structure from its conducting form. To address this, we identify and solve the structure with a different monobody that only partially blocks fluoride currents. The structure of the channel-monobody complex is asymmetric, with monobody bound to one side of the channel only. The channel conformation is nearly identical on the bound and uncomplexed sides, and to all previously solved structures, providing direct structural evidence that monobody binding does not induce local structural changes. Graphical Abstract Highlights • Inhibitory crystallization chaperones bind on each side of the membrane • Crystal structure of channel with one side free of chaperone binding • S8 chaperone-bound channel is competent for fluoride transport • Chaperones inhibit channels via a “cork-in-bottle” mechanism of physical occlusion McIlwain et al. present the structure of a fluoride channel bound to an inhibitory chaperone (monobody) on one side. Comparing to previous structures with chaperones on both sides, the authors show that monobody binding does not affect the structure of the channel, likely using physical occlusion to block the channel. |
| Databáze: | OpenAIRE |
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