Distinct structural elements that direct solution aggregation and membrane assembly in the channel-forming peptide...

Area of Science:

• Biophysics
• Molecular Biology
• Drug Discovery

Background:

• Cystic Fibrosis (CF) treatment strategies aim to restore chloride ion transport.
• Channel-forming peptides offer a potential therapeutic approach for CF by creating anion-selective pores.
• Efficient delivery of therapeutic peptides to airway cells is crucial for treatment efficacy.

Purpose of the Study:

• To investigate the structure-activity relationship of truncated M2GlyR peptides for chloride channel formation.
• To identify minimal peptide sequences capable of restoring chloride conductance.
• To understand the role of N-terminal and C-terminal domains in peptide aggregation and channel function.

Main Methods:

• Synthesis of N-terminal and C-terminal truncated M2GlyR peptides of varying lengths.
• Measurement of short-circuit current (I(SC)) to assess chloride conductance.
• Circular Dichroism (CD) spectroscopy to analyze peptide secondary structure in aqueous solution and TFE.
• Synthesis of palindromic peptide sequences to probe domain-specific functions.

Main Results:

• N-terminal truncated peptides, as short as 16 amino acids, effectively stimulated I(SC).
• C-terminal truncated peptides showed significantly reduced or no I(SC) stimulation below 27 amino acids.
• Helical propensity in TFE correlated with I(SC) stimulation, indicating a role in channel formation.
• Distinct regions governing solution aggregation and membrane channel assembly were identified.

Conclusions:

• Short N-terminal M2GlyR peptides retain significant channel-forming activity.
• Peptide sequence truncation impacts aggregation and channel function differently for N- and C-termini.
• Optimized peptides can eliminate aggregation while preserving channel activity, advancing CF therapeutic development.