Cotranslocational processing of the protein substrate calmodulin by an AAA+ unfoldase occurs via unfolding and refolding intermediates.

ABSTRACT: Protein remodeling by AAA+ enzymes is central for maintaining proteostasis in a living cell. However, a detailed structural description of how this is accomplished at the level of the substrate molecules that are acted upon is lacking. Here, we combine chemical cross-linking and methyl transverse relaxation-optimized NMR spectroscopy to study, at atomic resolution, the stepwise unfolding and subsequent refolding of the two-domain substrate calmodulin by the VAT AAA+ unfoldase from Thermoplasma acidophilum By engineering intermolecular disulphide bridges between the substrate and VAT we trap the substrate at different stages of translocation, allowing structural studies throughout the translocation process. Our results show that VAT initiates substrate translocation by pulling on int

SUBMITTER: Augustyniak R 

PROVIDER: S-EPMC6003507 | biostudies-literature | 2018 May

REPOSITORIES: biostudies-literature