Micelle-Triggered b-Hairpin to a-Helix Transition in a 14-Residue Peptide from aBinding Choline- Repeat of the Pneumococcal Autolysin LytA
Choline-binding modules (CBMs) have a bb-solenoid structure composed of choline-binding repeats (CBR), which consist of a b-hairpin followed by a short linker. To find minimal peptides that are able to maintain the CBR native structure and to evaluate their remaining cholinebinding ability, we have...
| Autores: | , , , , , |
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| Tipo de recurso: | artículo |
| Fecha de publicación: | 2015 |
| País: | España |
| Institución: | Universidad Miguel Hernández de Elche |
| Repositorio: | REDIUMH. Depósito Digital de la UMH |
| OAI Identifier: | oai:dspace.umh.es:11000/30956 |
| Acceso en línea: | https://hdl.handle.net/11000/30956 |
| Access Level: | acceso abierto |
| Palabra clave: | micelles protein folding protein structures structural biology structural elucidation |
| Sumario: | Choline-binding modules (CBMs) have a bb-solenoid structure composed of choline-binding repeats (CBR), which consist of a b-hairpin followed by a short linker. To find minimal peptides that are able to maintain the CBR native structure and to evaluate their remaining cholinebinding ability, we have analysed the third b-hairpin of the CBM from the pneumococcal LytA autolysin. Circular dichroism and NMR data reveal that this peptide forms a highly stable native-like b-hairpin both in aqueous solution and in the presence of trifluoroethanol, but, strikingly, the peptide structure is a stable amphipathic a-helix in both zwitterionic (dodecylphosphocholine) and anionic (sodium dodecylsulfate) detergent micelles, as well as in small unilamellar vesicles. This b-hairpin to a-helix conversion is reversible. Given that the b-hairpin and a-helix differ greatly in the distribution of hydrophobic and hydrophilic side chains, we propose that the amphipathicity is a requirement for a peptide structure to interact and to be stable in micelles or lipid vesicles. To our knowledge, this “chameleonic” behaviour is the only described case of a micelle-induced structural transition between two ordered peptide structures. |
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