The transthyretin (TTR) tetramer, assembled as a dimer of dimers, transports thyroxine and retinol binding protein in blood plasma and cerebrospinal fluid. Aggregation of wild type (WT) or pathogenic variant TTR leads to transthyretin amyloidosis, which is associated with neurodegenerative and cardiac disease. The trigger for TTR aggregation under physiological conditions is unknown. The tetramer is extremely stable at neutral pH, but aggregation via tetramer dissociation and monomer misfolding can be induced in v…

Intrinsically disordered proteins that mediate the cellular transcriptional response to hypoxia play important roles in regulating oxygen stress genes. The feedback inhibitor CITED2 operates a unidirectional switch that efficiently terminates the hypoxic response by displacing the C-terminal activation domain of the hypoxia-inducible factor HIF-1α from its complex with the TAZ1 domain of the transcriptional coactivators CBP and p300. Unidirectionality of the switch arises from subtle allosteric conformational chan…

Abstract Intrinsically disordered proteins that mediate the cellular transcriptional response to hypoxia play important roles in turning on and turning off oxygen stress genes. In particular, the feedback inhibitor CITED2 operates a unidirectional switch that efficiently terminates the hypoxic response by displacing the C-terminal activation domain of the hypoxia-inducible factor HIF-1α from its complex with the TAZ1 domain of the transcriptional coactivators CBP and p300. Unidirectionality of the switch arises fr…

The proper assembly of light-harvesting complexes (LHCs) is critical for photosynthesis and requires the biogenesis of light-harvesting chlorophyll a , b -binding proteins (LHCPs) to be coordinated with chlorophyll (Chl) biosynthesis. The mechanism underlying this coordination is not well understood. Here, we show that a conserved molecular chaperone, chloroplast signal recognition particle 43-kDa protein (cpSRP43), provides a molecular thermostat that helps maintain this coordination. cpSRP43 undergoes a conforma…

Abstract We have used nuclear magnetic resonance (NMR) spectroscopy to characterize dynamics in the bacterial oxidoreductase enzyme Escherichia coli disulfide bond protein A ( Ec DsbA). Through this process we identified a cryptic pocket in the structure. We demonstrate that we can identify small molecule “fragments” that bind entirely within this cryptic site. The fragments bind to the cryptic pocket with unusually slow kinetics and a preference for interacting with the oxidized state of Ec DsbA where the two cys…