Dipicolylamine as a unique structural switching element for helical peptides

Area of Science:

• Biomaterials Science
• Peptide Chemistry
• Metal-Organic Chemistry

Background:

• Developing functional biomolecules and biomaterials relies on novel methods for controlling molecular structures.
• Metal-induced structural changes in peptides offer new design principles for advanced materials.

Purpose of the Study:

• To develop a simple on-resin synthesis method for dipicolylamine (Dpa)-containing peptides.
• To investigate the metal-binding properties of Dpa-containing peptides and their potential for structural switching.
• To explore the application of these peptides in selective metal ion detection and reversible structural modulation.

Main Methods:

• On-resin synthesis of peptides incorporating dipicolylamine (Dpa) moieties at specific positions (i and i+4).
• Complexation studies with various divalent metal ions, including Fe(ii), Cu(ii), and Ni(ii).
• Spectroscopic analysis to characterize the resulting peptide-metal complexes and structural changes.

Main Results:

• A straightforward on-resin synthesis of Dpa-containing peptides was established.
• Divalent metal ions Fe(ii) and Cu(ii) formed 1:1 complexes with Dpa moieties.
• Ni(ii) induced a unique 2:1 cross-linked Dpa-metal structure, enabling selective Ni(ii) detection.
• The peptide-Fe(ii) complex facilitated selective Ni(ii) detection.
• Repeated metal ion addition induced reversible switching of the peptide's helical structure.

Conclusions:

• The developed Dpa-peptide system offers a versatile platform for metal-induced structural control.
• This method allows for the selective detection of Ni(ii) ions.
• The reversible structural switching capability opens avenues for designing responsive biomaterials and sensors.