Carboxyl terminus of Hsp70 interacting protein (CHIP) is a dimeric co-chaperone involved in providing an appropriate
balance between the synthesis and degradation of proteins, which is essential for normal cellular growth and
function. Previous work has shown that CHIP, but not its isolated domains, has chaperone activity that is enhanced by
heat. In this work, we investigate how heat and urea affect the stability of its domains. We found that the deletion mutant
containing the TPR domain, which binds to chaperones Hsp70 or Hsp90, was monomeric and showed similar folding and
stability to WT, while the mutant containing the U-box ubiquitin ligase domain was dimeric but had very low stability.
The deletion mutants appeared to maintain most of their structure compared to the WT protein, but the regions around the
tryptophan residues, which are at the interface of the domains in the WT structure, appeared to be more unfolded, which
indicated that the region of contact between domains is likely important for the chaperone function.