Characterization of the active intermediate of a GroEL-GroES-mediated protein folding reaction

Article Abstract:

GroEL is the most widely studied member of the chaperonin family that is found in the Escherichia coli cytoplasm. It plays an essential role in mediating protein folding in the cytosol of many cell types. Recent studies of GroE-mediated folding showed that the presence of GroEL mutants, called GroES, do not inhibit GroEL productive folding. However, the addition of ATP in the presence of GroES causes a rapid change in substrate flexibility at GroEL. This suggests that the cis ternary complex which is activated in the presence of ATP is the active element in GroE-mediated protein folding.

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Loops in the central channel of ClpA chaperone mediate protein binding, unfolding, and translocation

Article Abstract:

Chemical crosslinking and functional studies are carried out to explore the topology and mechanism of ClpA action. The ATPase domain (D2) loop binds substrates proximally and, coupled with ATP hydrolysis, translocates them distally, exerting mechanical force that mediates unfolding.

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GroEL/GroES-mediated folding of a protein too large to be encapsulated

Article Abstract:

Research demonstrates that mature forms of the heat shock proteins GroEL and GroES produce an active enzyme, chaperonin system, which mediates folding of larger proteins as illustrated by yeast mitochondrial aconitase.

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