Tailoring tissue inhibitor of metalloproteinases-3 to overcome the weakening effects of the cysteine-rich domains of tumour necrosis factor-α converting enzyme

Tumour necrosis factor-α (TNF-α) converting enzyme (TACE) is a membrane-anchored, multiple-domain zinc metalloproteinase responsible for the release of the potent pro-inflammatory cytokine, TNF-α. The extracellular part of the active enzyme is composed of a catalytic domain and several cysteine-rich domains. Previously, we reported that these cysteine-rich domains significantly weakened the inhibitory potency of the N-terminal-domain form of tissue inhibitor of metalloproteinases-3 (N-TIMP-3). In the present paper, we describe a novel strategy developed to overcome this weakening effect. We have engineered a new generation of N-TIMP-3 mutants that are capable of withstanding the repulsion of the cysteine-rich domains by the formation of electrostatic bonds with the catalytic domain of the enzyme. These N-TIMP-3 mutants displayed markedly improved binding affinity with the soluble extracellular domain form of recombinant TACE. With Ki (app) values of