Vault nanocapsule dissociation into halves triggered at low pH

Area of Science:

• Biochemistry
• Nanotechnology
• Structural Biology

Background:

• Vaults are ubiquitous ribonucleoprotein nanocapsules in eukaryotic cells with undetermined functions.
• Their potential applications in drug delivery and nanomaterials synthesis necessitate understanding their structural dynamics.

Purpose of the Study:

• To investigate recombinant vault conformational changes in response to varying solution pH.
• To identify conditions for reversible vault disassembly and reassembly.

Main Methods:

• Fluorescence spectroscopy to monitor changes in intrinsic fluorescence intensity.
• Multiangle laser light scattering (MALLS) to assess molecular mass and radius of gyration.
• Quartz crystal microbalance (QCM) to study vault adsorption and dissociation.
• Transmission electron microscopy (TEM) for visual confirmation of structural changes.

Main Results:

• A 60% increase in fluorescence intensity at pH 3.4 compared to pH 6.5 indicated a more open vault conformation at low pH.
• MALLS data revealed decreased molecular mass and increased radius of gyration at low pH, suggesting partial dissociation.
• QCM and TEM provided further evidence of vault disassembly into halves at pH 3.4.

Conclusions:

• Recombinant vaults exhibit pH-dependent conformational changes, including disassembly at acidic pH.
• These findings provide insights into vault structural dynamics and potential for controlled disassembly/reassembly.