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In the present contribution, we report a combined spectroscopic and computational approach aiming to unravel at atomic resolution the effect of the anionic SDS detergent on the structure of two model peptides, the α-helix TrpCage and the β-stranded TrpZip. A detailed characterization of the specific amino acids involved is performed. Monomeric (single molecules) and micellar SDS species differently interact with the α-helix and β-stranded peptides, emphasizing the different mechanisms occurring below and above the critical aggregation concentration (CAC). Below the CAC, the α-helix peptide is fully unfolded, losing its hydrophobic core and its Asp-Arg salt bridge, while the β-stranded peptide keeps its native structure with its four Trp well oriented. Above the CAC, the SDS micelles have the same effect on both peptides, that is, destabilizing the tertiary structure while keeping their secondary structure. Our studies will be helpful to deepen our understanding of the action of the denaturant SDS on peptides and proteins.

Original publication

DOI

10.1016/j.saa.2017.09.056

Type

Journal article

Journal

Spectrochim Acta A Mol Biomol Spectrosc

Publication Date

05/02/2018

Volume

190

Pages

464 - 470

Keywords

Molecular dynamics, Peptides, SDS, Spectroscopy, Surfactant