Probing the functional role of the N-terminal region of cystatins by equilibrium and kinetic studies of the binding of Gly-11 variants of recombinant human cystatin C to target proteinases
The interaction between cystatin C variants, in which the evolutionarily conserved Gly-11 residue was substituted by Ala, Glu or Trp, and the cysteine proteinases, papain, ficin, actinidin and cathepsin B, was characterized. The substitutions reduced the affinity of binding in a manner consistent with the Gly residue of the wild-type inhibitor, allowing the N-terminal region to adopt a conformatio