Binding and conformation of denatured horseradish peroxidase during E. coli ribosome mediated folding

Abstract

Denatured horseradish peroxidase (HRP) refolded in the presence of intact 70S E. coli ribosome. Fluorescence spectroscopic evidence of direct physical association between the ribosome particles and the denatured HRP during refolding has been detected. The efficiency of energy transfer from the single tryptophan (Trp) to the heme moiety and the quenching patterns of the Trp fluorescence by iodide and acrylamide differed with time while folding in the presence and absence of ribosome. An estimate of the binding of denatured fluorescein-conjugated HRP with ribosome was obtained from polarization measurements (K_d = 41 nM).