Refolding of yeast enolase in the presence of the chaperonin GroE. The nucleotide specificity of GroE and the role of GroES

GroE, a chaperonin protein from Escherichia coli, facilitates the folding of numerous proteins by binding to protein-folding intermediates and suppressing aggregation (Gething, M., and Sambrook, J. (1992) Nature 355, 33-45). The specific mechanism of GroE-facilitated folding involves numerous interactions between GroEL, GroES, the refolding protein, and ATP. In the present study, we have probed the molecular characteristics of the refolding reaction of yeast enolase in the presence of GroE. We have found that (a) GroEL interacts specifically with enolase during the folding reaction, resulting in folding arrest; (b) the release of partially folded molecules of enolase from the GroE complex may be mediated by the addition of nucleotides other than ATP (ADP, CTP, and UTP); and (c) GroES is required for enolase to be released from GroEL in the presence of ADP, CTP, and UTP but not required in the presence of ATP. The nucleotide binding mechanism of GroEL and the specific role of GroES during the refolding reaction are discussed in detail.