Solution structure of a two-repeat fragment of major vault protein

Area of Science:

• Structural Biology
• Molecular Biology
• Biochemistry

Background:

• Major vault protein (MVP) forms vaults, large ribonucleoprotein particles.
• Vaults are implicated in cancer therapy resistance and poor survival prognosis.

Purpose of the Study:

• To determine the structure of the main repeat element in human MVP.
• To model the assembly of MVP into the vault structure.
• To identify MVP's interaction sites with other vault components.

Main Methods:

• Solution Nuclear Magnetic Resonance (NMR) spectroscopy to determine the structure of MVP domains.
• Computational modeling to simulate MVP assembly into the vault.
• Chemical shift perturbation studies to map protein-protein interaction sites.

Main Results:

• The MVP domain exhibits a unique, novel fold with a three-stranded antiparallel beta-sheet.
• The solution NMR structure of a two-domain fragment elucidated interdomain contacts and orientations.
• A model for the assembly of 672 MVP domains into the 13 MDa vault structure was proposed.
• MVP domains were identified as a new class of interaction-mediating modules, binding vault poly(ADP-ribose) polymerase.

Conclusions:

• The determined MVP structure provides insights into vault self-assembly.
• MVP domains mediate interactions with other vault components, like vault poly(ADP-ribose) polymerase.
• This work lays the foundation for understanding vault function in cancer therapy.