title: Interaction of oxidized chaperonin GroEL with an unfolded protein at low temperatures.
abstract: The chaperonin GroEL binds to non-native substrate proteins via hydrophobic interactions, preventing their aggregation, which is minimized at low temperatures. In the present study, we investigated the refolding of urea-denatured rhodanese at low temperatures, in the presence of ox-GroEL (oxidized GroEL), which contains increased exposed hydrophobic surfaces and retains its ability to hydrolyse ATP. We found that ox-GroEL could efficiently bind the urea-unfolded rhodanese at 4°C, without requiring excess amount of chaperonin relative to normal GroEL (i.e. non-oxidized). The release/reactivation of rhodanese from GroEL was minimal at 4°C, but was found to be optimal between 22 and 37°C. It was found that the loss of the ATPase activity of ox-GroEL at 4°C prevented the release of rhodanese from the GroEL-rhodanese complex. Thus ox-GroEL has the potential to efficiently trap recombinant or non-native proteins at 4°C and release them at higher temperatures under appropriate conditions.
authors.affiliation: Department of Biology and Molecular Biology Institute, San Diego State University, San Diego, CA 92182-4614, USA.
authors.forename: Girish C
authors.initials: GC
authors.lastname: Melkani
authors.forename: Robin
authors.initials: R
authors.lastname: Sielaff
authors.forename: Gustavo
authors.initials: G
authors.lastname: Zardeneta
authors.forename: Jose A
authors.initials: JA
authors.lastname: Mendoza
mesh_terms: D000818:Animals; D002417:Cattle; D018834:Chaperonin 60 / Q000737:chemistry*; D003080:Cold Temperature; D007700:Kinetics; D008099:Liver / Q000201:enzymology; D010084:Oxidation-Reduction; D011485:Protein Binding; D011489:Protein Denaturation; D058849:Protein Refolding; D013884:Thiosulfate Sulfurtransferase / Q000737:chemistry*; D014508:Urea / Q000737:chemistry
chemical_list: D018834:Chaperonin 60; D014508:Urea; D013884:Thiosulfate Sulfurtransferase