Kinetic intermediates in the formation of ordered complexes from cytochrome c fragments. Evidence that methionine ligation is a late event in the folding process.

摘要: The reactions of ferric heme-containing fragments with apofragments to form ordered complexes resembling native horse heart cytochrome c have been studied under conditions which resolve the overall process into consecutive second order and first kinetic steps. In initial, step two combine an intermediate complex exhibits tryptophan 59 fluorescence quenching similar c, but has not yet achieved ligation state heme iron. existence processes following is demonstrated by absorbance changes in Soret region. entire change at 695 nm, relating sulfur atom methionine 80 iron, also associated these processes. Thus, a late event this self ordering polypeptide chains. Since conformational energy assumed distinctly decrease folding (Parr, G.R., Taniuchi, H. (1980) J. Biol. Chem. 255, 2616-2623), it would follow that small spatial rearrangements chains stage (as manifested methionine) are specific energy.