Biochemical and Molecular Characterization of a Novel Cu/Zn Superoxide Dismutase from Amaranthus hypochondriacus L.: an Intrinsically Disordered Protein

摘要: A novel Cu/ZnSOD from Amaranthus hypochondriacus was cloned, expressed, and characterized. Nucleotide sequence analysis showed an open reading frame (ORF) of 456 bp, which predicted to encode a 15.6-kDa molecular weight protein with pI 5.4. Structural highly conserved amino acid residues involved in Cu/Zn binding. Recombinant amaranth superoxide dismutase (rAhSOD) displayed more than 50 % catalytic activity after incubation at 100 °C for 30 min. In silico SOD (AhSOD) globularity disorder suggested that this is mainly disordered; confirmed by circular dichroism, the lack secondary structure. Intrinsic fluorescence studies rAhSOD undergoes conformational changes two steps presence Cu/Zn, indicates binding sites displaying different affinities metals ions. Our results show AhSOD could be classified as intrinsically disordered (IDP) folded when are bound high thermal stability.