Inducing α‐Helicity in Peptides by Silver Coordination to Cysteine

Short peptide sequences consisting of two cysteine residues separated by three other amino acids display complete change from random coil to α‐helical secondary structure in response to addition of Ag+ ions. The folded CXXXC/Ag+ complex involves formation of multinuclear Ag+ species and is stable in...

Full description

Saved in:
Bibliographic Details
Published in:Chemistry : a European journal 2024-06, Vol.30 (31), p.e202304064-n/a
Main Authors: Fischer, Niklas, Tóth, Annamária, Jancsó, Attila, Thulstrup, Peter, Diness, Frederik
Format: Article
Language:English
Subjects:
Amino acids
Chloride ions
Circular dichroism
Cysteine
Dichroism
Dimers
Folding
Helicity
Ions
Liquid chromatography
Nucleation
Oligomerization
peptide
Peptides
pH effects
Protein structure
Random coil
Secondary structure
Silver
Spectroscopy
α-helix
Citations: Items that this one cites
Online Access:Get full text
Tags: Add Tag
No Tags, Be the first to tag this record!
Description
Summary:Short peptide sequences consisting of two cysteine residues separated by three other amino acids display complete change from random coil to α‐helical secondary structure in response to addition of Ag+ ions. The folded CXXXC/Ag+ complex involves formation of multinuclear Ag+ species and is stable in a wide pH range from below 3 to above 8. The complex is stable through reversed‐phase HPLC separation as well as towards a physiological level of chloride ions, based on far‐UV circular dichroism spectroscopy. In electrospray MS under acidic conditions a peptide dimer with four Ag+ ions bound was observed, and modelling based on potentiometric experiments supported this to be the dominating complex at neutral pH together with a peptide dimer with 3 Ag+ and one proton at lower pH. The complex was demonstrated to work as a N‐terminal nucleation site for inducing α‐helicity into longer peptides. This type of silver‐mediated peptide assembly and folding may be of more general use for stabilizing not only peptide folding but also for controlling oligomerization even under acidic conditions. A molecular switch based on metal complexation of peptides is here presented. The highly ordered dimeric α‐helical complexes are obtained by adding silver ions to specific peptide motifs containing two cysteine residues. The dynamic formation of these surprisingly stable complexes has been characterized by chromatographic, spectroscopic, potentiometric and mass spectrometric methods.
ISSN:0947-6539
1521-3765
DOI:10.1002/chem.202304064