An outmoded in vitro-inferred mechanism for chaperonin-accelerated protein refolding is confirmed in cells by cryo-electron tomography

A recent elegant cryo-electron tomography study of the populations of different GroEL-GroES chaperonins complexes in whole bacterial cells (Wagner, Carvajal et al. 2024) contributes to the resolution of a long-standing debate about their mechanism, and reconciles three-decade-old results from in vitro biochemical studies, with new, refined in situ observations. Biochemists working with purified proteins often wonder if their findings faithfully reflect the situation in the crowded environment of cells, when their proteins mingle with concentrated metabolites and bump into membranes and thousands of different unrelated proteins. Here, cryo-electron tomography confirmed that careful in vitro protein biochemistry research still has a bright future.