title: Human cathepsin L, a papain-like collagenase without proline specificity.
abstract: Several members of the papain-like peptidase family have the ability to degrade collagen molecules by cleaving within the triple helix region of this difficult substrate. A common denominator of these peptidases is their ability to cleave substrates with Pro in the P2 position. In humans, cathepsin K is the best-known papain-like collagenase. Here, we investigate the collagenolytic activity of human cathepsin L, which is closely related to cathepsin K. We show that, despite lacking proline specificity, cathepsin L efficiently cleaves type I collagen within the triple helix region and produces a cleavage pattern similar to that of cathepsin K. We demonstrate that both enzymes have similar affinities for type I collagen and are able to release proteolytic fragments from insoluble collagen. Moreover, cathepsin K is only approximately fourfold more potent than cathepsin L in releasing fragments from reconstituted fibrils of FITC-labeled collagen. Replacing active site residues of cathepsin L with those from cathepsin K introduces cathepsin K-like specificity towards synthetic substrates and increases the collagenolytic activity of cathepsin L. Replacing three residues in the S2 subsite is sufficient to produce a mutant with collagenolytic activity on par with human cathepsin K. These results provide a basis for engineering collagenolytic activity into non-collagenolytic papain-like scaffolds.
authors: Department of Chemistry and Biochemistry, Faculty of Chemistry and Chemical Technology, University of Ljubljana, Slovenia.
authors: Matevž
authors: M
authors: Korenč
authors: Department of Chemistry and Biochemistry, Faculty of Chemistry and Chemical Technology, University of Ljubljana, Slovenia.|Department of Biochemistry and Molecular and Structural Biology, Jožef Stefan Institute, Ljubljana, Slovenia.
authors: Brigita
authors: B
authors: Lenarčič
authors: Department of Chemistry and Biochemistry, Faculty of Chemistry and Chemical Technology, University of Ljubljana, Slovenia.
authors: Marko
authors: M
authors: Novinec
mesh_terms: D056657:Cathepsin K / Q000378:metabolism; D056668:Cathepsin L / Q000235:genetics / Q000378:metabolism*; D024042:Collagen Type I / Q000378:metabolism; D006801:Humans; D006863:Hydrogen-Ion Concentration; D011392:Proline / Q000378:metabolism; D013379:Substrate Specificity
chemical_list: D024042:Collagen Type I; D011392:Proline; D056668:Cathepsin L; D056657:Cathepsin K
keywords: cancer; collagen; cysteine peptidase; proteolysis; triple helix