Nucleotide specificity of an archaeal group II chaperonin from Thermococcus strain KS-1 with reference to the ATP-dependent protein folding cycle

The archaeal chaperonin-mediated folding of green fluorescent protein (GFP) was examined in the presence of various nucleotides. The recombinant alpha- and beta-subunit homo-oligomers and natural chaperonin oligomer from Thermococcus strain KS-1 exhibited folding activity with not only ATP but also with CTP, GTP, or UTP. The ADP-bound form of both recombinant and natural chaperonin had the ability to capture non-native GFP, but could not refold it in the presence of CTP, GTP or UTP until ATP was supplied. The archaeal chaperonin thus utilized ATP, but could not use other nucleoside triphosphates in the cytoplasm where ADP was present.