Premium
Micelle‐Triggered β‐Hairpin to α‐Helix Transition in a 14‐Residue Peptide from a Choline‐Binding Repeat of the Pneumococcal Autolysin LytA
Author(s) -
ZamoraCarreras Héctor,
Maestro Beatriz,
Strandberg Erik,
Ulrich Anne S.,
Sanz Jesús M.,
Jiménez M. Ángeles
Publication year - 2015
Publication title -
chemistry – a european journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.687
H-Index - 242
eISSN - 1521-3765
pISSN - 0947-6539
DOI - 10.1002/chem.201500447
Subject(s) - micelle , chemistry , autolysin , circular dichroism , amphiphile , peptide , vesicle , helix (gastropod) , biophysics , crystallography , stereochemistry , aqueous solution , biochemistry , organic chemistry , mutant , polymer , biology , copolymer , ecology , membrane , snail , gene
Choline‐binding modules (CBMs) have a ββ‐solenoid structure composed of choline‐binding repeats (CBR), which consist of a β‐hairpin followed by a short linker. To find minimal peptides that are able to maintain the CBR native structure and to evaluate their remaining choline‐binding ability, we have analysed the third β‐hairpin of the CBM from the pneumococcal LytA autolysin. Circular dichroism and NMR data reveal that this peptide forms a highly stable native‐like β‐hairpin both in aqueous solution and in the presence of trifluoroethanol, but, strikingly, the peptide structure is a stable amphipathic α‐helix in both zwitterionic (dodecylphosphocholine) and anionic (sodium dodecylsulfate) detergent micelles, as well as in small unilamellar vesicles. This β‐hairpin to α‐helix conversion is reversible. Given that the β‐hairpin and α‐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.