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Cryo-EM structure of the diapause chaperone artemin.

Frontiers in molecular biosciences (2022-12-16)
Amar D Parvate, Samantha M Powell, Jory T Brookreson, Trevor H Moser, Irina V Novikova, Mowei Zhou, James E Evans
ABSTRACT

The protein artemin acts as both an RNA and protein chaperone and constitutes over 10% of all protein in Artemia cysts during diapause. However, its mechanistic details remain elusive since no high-resolution structure of artemin exists. Here we report the full-length structure of artemin at 2.04 Å resolution. The cryo-EM map contains density for an intramolecular disulfide bond between Cys22-Cys61 and resolves the entire C-terminus extending into the core of the assembled protein cage but in a different configuration than previously hypothesized with molecular modeling. We also provide data supporting the role of C-terminal helix F towards stabilizing the dimer form that is believed to be important for its chaperoning activity. We were able to destabilize this effect by placing a tag at the C-terminus to fully pack the internal cavity and cause limited steric hindrance.

MATERIALS
Product Number
Brand
Product Description

Millipore
ANTI-FLAG® M2 Affinity Gel, purified immunoglobulin, buffered aqueous glycerol solution
Sigma-Aldrich
Protease Inhibitor Cocktail Set V, EDTA-Free, A cocktail of four protease inhibitors for the inhibition of serine, cysteine, but not metalloproteases.