Phase-dependent redox insulation in mussel adhesion.

Area of Science:

• Biochemistry
• Materials Science
• Marine Biology

Background:

• Mussel foot proteins (mfps) contain 3,4-dihydroxyphenyl-l-alanine (Dopa) residues essential for plaque adhesion.
• Dopa residues are prone to oxidation in seawater, yet are protected within mussel plaques.

Purpose of the Study:

• Investigate the mechanism by which mussel plaques insulate Dopa-containing mfps from oxidation.
• Understand the role of liquid-liquid phase separation (LLPS) in maintaining protein stability.

Main Methods:

• Combined plaque cyclic voltammetry with electrophoresis, mass spectrometry, and redox-exchange chemistry.
• Studied the effect of seawater sulfate on mfp3 and mfp6 liquid-liquid phase separation.

Main Results:

• Seawater sulfate induces LLPS of mfp3 and mfp6.
• Dopa-containing mfp3 and mfp6 within phase-separated droplets exhibit redox stability.
• Proteins in LLPS compartments become reservoirs of chemical energy.

Conclusions:

• Mussel plaque formation involves LLPS that confers redox stability to Dopa-containing proteins.
• Phase-dependent redox stability is a key strategy for oxidation-prone proteins.
• LLPS compartments act as energy reservoirs, crucial for mussel adhesion.