Group II chaperonins,which assemble as double-ring complexes,assist in the refolding of nascent peptides or denatured proteins in an ATP-dependent manner.The mo-lecular mechanism of group II chaperonin assembly and th...Group II chaperonins,which assemble as double-ring complexes,assist in the refolding of nascent peptides or denatured proteins in an ATP-dependent manner.The mo-lecular mechanism of group II chaperonin assembly and thermal stability is yet to be elucidated.Here,we selected the group II chaperonins(cpn-αand cpn-β),also called thermosomes,from Acidianus tengchongensis and in-vestigated their assembly and thermal stability.We found that the binding of ATP or its analogs contributed to the successful assembly of thermosomes and enhanced their thermal stabilities.Cpn-βis more thermally stable than cpn-α,while the thermal stability of the hetero thermo-some cpn-αβis intermediate.Cryo-electron microscopy reconstructions of cpn-αand cpn-βrevealed the interwo-ven densities of their non-conserved fl exible N/C-termini around the equatorial planes.The deletion or swapping of their termini and pH-dependent thermal stability assays revealed the key role of the termini electrostatic interac-tions in the assembly and thermal stability of the ther-mosomes.展开更多
文摘Group II chaperonins,which assemble as double-ring complexes,assist in the refolding of nascent peptides or denatured proteins in an ATP-dependent manner.The mo-lecular mechanism of group II chaperonin assembly and thermal stability is yet to be elucidated.Here,we selected the group II chaperonins(cpn-αand cpn-β),also called thermosomes,from Acidianus tengchongensis and in-vestigated their assembly and thermal stability.We found that the binding of ATP or its analogs contributed to the successful assembly of thermosomes and enhanced their thermal stabilities.Cpn-βis more thermally stable than cpn-α,while the thermal stability of the hetero thermo-some cpn-αβis intermediate.Cryo-electron microscopy reconstructions of cpn-αand cpn-βrevealed the interwo-ven densities of their non-conserved fl exible N/C-termini around the equatorial planes.The deletion or swapping of their termini and pH-dependent thermal stability assays revealed the key role of the termini electrostatic interac-tions in the assembly and thermal stability of the ther-mosomes.
