Membrane permeabilization and efficient gene transfer by a peptide containing several histidines

Area of Science:

• Biochemistry
• Molecular Biology
• Biotechnology

Background:

• Cell membrane permeabilization is crucial for cytosolic delivery of molecules.
• Peptide-based delivery systems offer potential for enhanced cellular uptake.
• pH-sensitive peptides can target specific cellular compartments or conditions.

Purpose of the Study:

• To design and characterize a novel peptide, H5WYG, for pH-dependent cell membrane permeabilization.
• To evaluate the efficacy of H5WYG in enhancing gene transfection.
• To assess the utility of H5WYG as a helper molecule for cytosolic delivery.

Main Methods:

• Peptide design and synthesis (H5WYG).
• Spectroscopic analysis (absorbance, fluorescence, circular dichroism) to study conformational changes.
• Flow cytometry to monitor cell membrane permeabilization.
• Gene transfection assays using glycosylated polylysine-DNA complexes.

Main Results:

• H5WYG exhibits a significant conformational change between pH 7.0 and 6.0, linked to histidine protonation.
• H5WYG efficiently permeabilizes cell membranes at pH 6.4 and shows partial activity at pH 6.8.
• Transfection efficiency of DNA complexes was enhanced by H5WYG, with no impairment in serum.
• Peptide activity is dependent on slightly acidic pH, not neutral pH.

Conclusions:

• H5WYG is a pH-sensitive peptide capable of inducing cell membrane permeabilization.
• The peptide's histidine residues are key to its pH-dependent conformational change and activity.
• H5WYG is a promising helper molecule for enhancing cytosolic delivery and gene transfection, particularly in acidic environments.