Converging concepts of protein folding in vitro and in vivo

Abstract

Most proteins must fold into precise three-dimensional conformations to fulfill their biological functions. Here we review recent concepts emerging from studies of protein folding in vitro and in vivo, with a focus on how proteins navigate the complex folding energy landscape inside cells with the aid of molecular chaperones. Understanding these reactions is also of considerable medical relevance, as the aggregation of misfolding proteins that escape the cellular quality-control machinery underlies a range of debilitating diseases, including many age-onset neurodegenerative disorders.

SPY-ing into Protein Stability

“…Unlike many other ATP independent chaperones, e.g. DnaK and GroeL systems, it also helps in protein refolding [3]. This study is supported by the effects of Spy in preventing Malate dehydrogenase aggregation due to denaturation by urea.…”

Firefly luciferase mutants as sensors of proteome stress

“…About 10% of chains are co-or post-translationally transferred to the chaperonin TRiC/CCT by Hsp70 and prefoldin (PFD). Adapted from (Hartl and Hayer-Hartl, 2009). …”

Dual Binding Mode of the Nascent Polypeptide-associated Complex Reveals a Novel Universal Adapter Site on the Ribosome

“…The resulting supernatant was termed S100. Ribosomes were pelleted from this S100 extract through a high salt (500 mM KOAc) or low salt (100 mM KOAc) sucrose cushion (20 mM Hepes-KOH, pH 7.5, 100 -500 mM KOAc, 5 mM Mg(OAc) 2 2 , protease inhibitor mixture complete) for 2 min at 26°C followed by 5 min on ice. AMAS (N-(␣-maleimidoacetoxy)succinimide ester) in dimethyl sulfoxide was added to a final concentration of 1.6 mM.…”

“…Yeast cultures (W-303-1A or YJF24 expressing egd1 or egd2 from plasmids) were grown on YPD medium or the appropriate selection medium to an A 600 of 1.0 to 1.5. Cells were harvested (7.000 ϫ g, 6 min, 4°C), washed with ice-cold ddH 2 O followed by 1% KCl. Cells were then incubated in 100 mM Tris-HCl, pH 8.0, 10 mM DTT for 15 min at 30°C, pelleted again, resuspended in lysis buffer (20 mM Hepes-KOH, pH 7.5, 100 mM KOAc, 20 mM Mg(OAc) 2 , 4 mM DTT, 150 mM sucrose, 500 M phenylmethylsulfonyl fluoride, protease inhibitor mixture complete) and disrupted by 3 passages through an EmulsiFlex-C5 High Pressure homogenizer at 1,400 bar.…”