Triple Helicase Activity and the Structural Basis of Collagenolysis

Abstract

The degradation of interstitial collagens I, II and III is an integral part of many biological events such as embryonic development, organ morphogenesis, tissue remodelling and repair, and in diseases such as arthritis, cancer, atherosclerosis, aneurysm and fibrosis, but these collagens are resistant to most proteolytic enzymes due to their triple helical structures. In vertebrates, the enzymes that degrade interstitial collagens are collagenases that are members of the matrix metalloproteinase (MMP) family, and cathepsin K, a lysosomal cysteine proteinase. Non-vertebrate collagenases include collagenolytic serine proteinases in crustacea and Clostridium histolyticum collagenases, also called “bacterial collagenases.” This chapter describes the unique properties of these collagenolytic proteinases and the current proposal as to how they recognize triple helical structures and cleave them. Potential enzymatic pathways that may be involved in the degradation of collagen fibrils are also discussed.