Fig. 4.
The construction of polyprotein with pure metal form by OaAEP1. a The schematic shows that the recombinant DNA method-based polyprotein construction strategy results in a polyprotein (Rd)8 with protein domains of different and uncontrolled content (metal form). b By expressing the protein as a monomer, it can be purified first, and then be ligated as a pure metal-form polyprotein. c The UV-Vis absorbance spectra of purified rubredoxin monomers, GL--GB1-Fe(III)-Rd-NGL (Top spectrum, colored in green, PDB code for Fe(III)-Rd:1BRF) and GL--GB1-(Zn)-Rd-NGL (Bottom spectrum, colored in red, PDB code for Zn-Rd: 1IRN). The Fe(III)-form Rd showed a characteristic UV-Vis at the wavelength of 495 nm and 579 nm. d–f Pure metal form GL-(GB1-Rd)n-NGL, Fe(e) and Zn(f) built by OaAEP1 showed comparable AFM results as the bi-cysteine built polyprotein. The ΔLc value of ~13 nm is observed as expected for rubredoxin unfolding. Source data of Fig. 4c, e and f are provided as a Source Data file