11:115:301 Lecture Notes - Lecture 3: Hsp70, Groel, Groes
22 Sep 2019
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Document Summary
Protein folding is a fast stepwise process to find the lowest s. Increase denaturant spontaneous switch from folded to unfolded. Population consists of fully folded and fully unfolded forms. Lowest free entropy 100% aa"s in native conformation. Ex: g = -10 -(1)(-2) = -8 < 0 spontaneous. Artificial example - renaturation of chymotrypsin inhibitor. Renaturation of alpha helix a compact form formation of final beta. Mechanisms of the hsp70 and chaperonin systems - case when protein unfolds sheets. Hsp70 = heat shock proteins similar to dnak in bacteria. Unfolded protein (u) presented to atp-bound dnak by the hsp40 dnaj . Dnaj + dnak atp hydrolysis on dnak tight binding of u to dnak. U tightly bonded to adp-bound dnak grpe (nucleotide exchange factor) causes dissociation of adp (from dnak) atp can rebind dnak. Dnak shifted to low substrate affinity mode release u folding to native state.
