7/25/2023 0 Comments Molecular chaperone![]() ![]() Recent studies have also highlighted molecular chaperones as inhibitors of amyloid formation ( Mainz et al., 2015 Taylor et al., 2016). Thus, chaperones are central to protein homeostasis in the cell and are essential for life ( Hipp et al., 2014 Powers and Balch, 2013). Molecular chaperones typically prevent the aggregation and assist with the folding of non-native proteins ( Balchin et al., 2016 Bukau et al., 2006). Our results demonstrate how the activity of a chaperone can be modulated to provide distinct functional outcomes in the cell. The structural data show that the dimer assembles in a way that substrate-binding sites in the two subunits form a large contiguous surface inside a cavity, thus accounting for the observed accelerated association with unfolded proteins. Surprisingly, the dimeric TF associates faster with proteins and it exhibits stronger anti-aggregation and holdase activity than the monomeric TF. The structural data show that some of the substrate-binding sites are buried in the dimeric interface, explaining the lower affinity for protein substrates of the dimeric compared to the monomeric TF. We used NMR spectroscopy to determine the atomic resolution structure of the 100 kDa dimeric TF. Here, we show that Trigger Factor (TF), an ATP-independent chaperone, exerts strikingly contrasting effects on the folding of non-native proteins as it transitions between a monomeric and a dimeric state. Molecular chaperones alter the folding properties of cellular proteins via mechanisms that are not well understood. ![]()
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