Thermal unfolding of G‐actin monitored with the DNase I‐inhibition assay

摘要: Actin is one of the proteins that rely on chaperonins for proper folding. This paper shows thermal unfolding G-actin, as studied by CD and ultraviolet difference spectrometry, coincides with a loss in DNase I-inhibiting activity protein. Thus, DNase I inhibition assay should be useful systematic studies actin refolding. Using this assay, we have investigated how stability affected either Ca2 + or Mg2 + at high affinity divalent cation binding site, concentration excess nucleotide, nucleotide different states phosphorylation (ATP, ADP.Pi, ADP.Vi, ADP.AlF4, ADP.BeFx, ADP). isoforms from species were also compared, effect profilin was studied. We conclude G-actin three-state process, which an equilibrium exists between native bound intermediate free nucleotide. Actins Mg-form less stable than Ca-forms, decreased following order: rabbit skeletal muscle α-actin =  bovine cytoplasmic γ-actin >  yeast >  cytoplasmic β-actin. The activation energies reactions range 200–290 kJ·mol− 1, depending ligands. Generally, depended degree contributed to connectivity two domains