title: Further evidence on the equilibrium "pre-molten globule state": four-state guanidinium chloride-induced unfolding of carbonic anhydrase B at low temperature.
abstract: Equilibrium guanidinium chloride-induced unfolding of bovine carbonic anhydrase NB has been investigated by a combination of optical methods with size-exclusion chromatography. It has been shown that, as in the case of staphylococcal beta-lactamase, bovine carbonic anhydrase B unfolds at low temperature through two equilibrium intermediates; the molten globule and the pre-molten globule states. This pre-molten globule state has a hydrodynamic volume no more than twofold larger than that of the native state, i.e. is relatively compact. It has a pronounced far UV CD spectrum, suggesting the presence of a substantial secondary structure. It binds 8-anilinonaphthalene-1-sulphonate (though weaker than the molten globule state), which suggests the formation of solvent-exposed clusters of non-polar groups. Thus, this novel state of protein molecules shares a number of properties with the "burst" kinetic intermediate of protein folding and can be considered as its equilibrium counterpart.
authors.affiliation: Institute of Protein Research Russian Academy of Sciences, Pushchino, Moscow Region, Russia.
authors.forename: V N
authors.initials: VN
authors.lastname: Uversky
authors.forename: O B
authors.initials: OB
authors.lastname: Ptitsyn
mesh_terms: D000817:Anilino Naphthalenesulfonates / Q000378:metabolism; D000818:Animals; D002256:Carbonic Anhydrases / Q000737:chemistry* / Q000378:metabolism; D002417:Cattle; D003080:Cold Temperature; D005456:Fluorescent Dyes / Q000378:metabolism; D019791:Guanidine; D006146:Guanidines / Q000494:pharmacology*; D011489:Protein Denaturation / Q000187:drug effects; D017510:Protein Folding; D017433:Protein Structure, Secondary
chemical_list: D000817:Anilino Naphthalenesulfonates; D005456:Fluorescent Dyes; D006146:Guanidines; C027132:1-anilino-8-naphthalenesulfonate; D002256:Carbonic Anhydrases; D019791:Guanidine