Conformational ensemble of the TNF-derived peptide solnatide in solution

Area of Science:

• Biochemistry
• Structural Biology
• Pharmacology

Background:

• Tumor necrosis factor (TNF) is a cytokine with distinct binding regions, including lectin-like domains (LLD) crucial for certain activities.
• Solnatide (AP301) is a peptide that mimics the LLD of TNF, activating the epithelial sodium channel (ENaC).
• ENaC plays a vital role in lung liquid clearance, making solnatide a potential therapeutic for pulmonary edema in ARDS and severe COVID-19.

Purpose of the Study:

• To analyze the folding properties of solnatide using Nuclear Magnetic Resonance (NMR) spectroscopy.
• To propose a model for solnatide's interaction with the ENaCα subunit.
• To guide future experiments and the design of novel solnatide analogs.

Main Methods:

• Nuclear Magnetic Resonance (NMR) spectroscopy was employed to determine solnatide's solution structure.
• Structural information of solnatide and ENaC protein was used to develop an interaction model.
• Analysis of solnatide's conformations in solution.

Main Results:

• Solnatide populates multiple conformations in solution, featuring a hydrophobic core and charged poles.
• A model for solnatide interaction with the C-terminal domain of the ENaCα subunit was proposed.
• The study provides structural insights into solnatide's mechanism of action.

Conclusions:

• Solnatide's structural characterization provides a basis for understanding its ENaC-activating and therapeutic potential.
• The proposed interaction model can guide further validation studies and the development of improved solnatide analogs.
• This research supports solnatide's development as a treatment for lung liquid clearance disorders.