PURIFICATION AND CHARACTERIZATION OF CHAPERONIN-60 AND CHAPERONIN-10 FROM METHYLOBACILLUS GLYCOGENES

Two proteins belonging to the group I chaperonin family were isolated from an obligate methanotroph, Methylobacillus glycogenes. The two pro teins, one a GroEL homologue (cpn60: M. glycogenes 60 kDa chaperonin) and the other a GroES homologue (cpn10: M. glycogenes 10 kDa chaperoni n), composed a heteropolymeric complex in the presence of ATP. Both pr oteins were purified from crude extracts of M. glycogenes by anion-exc hange (DEAE-Toyopearl) and gel-filtration (Sephacryl S-400) chromatogr aphy The native molecular weights of each chaperonin protein as determ ined by high-performance liquid chromatography (HPLC) gel-filtration w ere 820000 for cpn60 and 65000 for cpn10. Sodium dodecyl sulfate-polya crylamide gel electrophoresis revealed that the subunit molecular weig hts of cpn60 and cpn10 were 58000 and 10000, respectively. Both cpn60 and cpn10 possessed amino acid sequences which were highly homologous to other group I chaperonins. NI. glycogenes cpn60 displayed an ATPase activity which was inhibited in the presence of cpn10. The chaperonin s also displayed an ability to interact with and facilitate the refold ing of Thermus malate dehydrogenase and yeast enolase in a manner simi lar to that of GroEL/ES. The similarities between the Escherichia coli GroE proteins are discussed.