Crystal structures of the two major aggrecan degrading enzymes, ADAMTS4 and ADAMTS5

Abstract

Aggrecanases are now believed to be the principal proteinases responsible for aggrecan degradation in osteoarthritis. Given their potential as a drug target, we solved crystal structures of the two most active human aggrecanase isoforms, ADAMTS4 and ADAMTS5, each in complex with bound inhibitor and one wherein the enzyme is in apo form. These structures show that the unliganded and inhibitor-bound enzymes exhibit two essentially different catalytic-site configurations: an autoinhibited, nonbinding, closed form and an open, binding form. On this basis, we propose that mature aggrecanases exist as an ensemble of at least two isomers, only one of which is proteolytically active.Keywords: protein structure; enzymes; metalloproteins; aggrecanases Supplemental material: see www.proteinscience.org Osteoarthritis (OA) is a progressive disease that results in degradation of articular cartilage and chronic pain. The extracellular matrix is composed of two major components, aggrecan and collagen. Aggrecan is a large multidomain proteoglycan that provides cartilage with compressibility and elasticity by swelling and hydrating the collagen network (Vertel and Ratcliffe 2000). Loss of aggrecan is considered a critical early event in OA, occurring initially at the joint surface and progressing to the deeper zones. This is followed by degradation of collagen fibrils and mechanical failure of the tissue (Nagase and Kashiwagi 2003). Aggrecanase-1 (ADAMTS4) and aggrecanase-2 (ADAMTS5), members of the ADAMTS (a disintegrin and metalloprotease with thrombospondin motifs) gene family, cleave aggrecan at a unique site termed the ''aggrecanase site Tortorella et al. 1999). ADAMTS4 and ADAMTS5 are expressed in human normal and OA cartilage (Yamanishi et al. 2002) and in OA synovium, and contribute to the structural damage that characterizes human OA (Powell et al. 2007;Song et al. 2007). However, there is no consensus in the literature as to which aggrecanase is the most important in human OA. In mice, ADAMTS5 (but not ADAMTS4) is responsible for disease progression in a surgically induced model of OA (Glasson et al. 2004(Glasson et al. , 2005. ADAMTS4/ADAMTS5 double knockout mice are physiologically normal (Majumdar et al. 2007) and also protected from developing OA. Given the normal phenotype of the double knockout mice, dual inhibition Article published online ahead of print. Article and publication date are at http://www.proteinscience.org/cgi

Mechanism of von Willebrand factor scissile bond cleavage by a disintegrin and metalloproteinase with a thrombospondin type 1 motif, member 13 (ADAMTS13)

“…The ADAMTS13 metalloprotease domain was initially modeled using the HHPred server based on its sequence homology to ADAMTS1, -4, and -5, for which the crystal structures are available (28)(29)(30). Models were manipulated with Pymol software (Delano Scientific LLC).…”

Molecular models of the Mojave rattlesnake (Crotalus scutulatus scutulatus) venom metalloproteinases reveal a structural basis for differences in hemorrhagic activities

“…Snake venom metalloproteinases (SVMPs) have evolved from an ancient mammalian ADAM gene [8][9][10]. Hence, SVMPs and ADAMs share a similar secondary structural organization [11][12][13][14][15][16]. These metalloproteinases are complex multi-domain proteins that are classified as P-I, P-II, and P-III based on the presence or absence of the non-catalytic ancillary domains that extend beyond the mature proteinase domain (P-I) [12,13,17].…”

Structure analysis reveals the flexibility of the ADAMTS‐5 active site

“…This observation is a novel finding that has not been observed before in any ADAMTS protein. However, the dynamic nature of the active site of ADAMTS enzymes has been suggested by Mosyak et al, 9 who point out that conformational mobility of the active site is a feature of mature aggrecanases that may be required for high affinity association with its substrates.…”

“…Achieving selectivity has been challenging because there are two related families of MPs sharing the zinc-binding consensus sequence, HEXXHXXXGXX, including 23 matrix metalloproteinases (MMPs), and 20 ADAMs. 6,7 However, recent elucidation of crystal structures for ADAMTS-1, 8 À4, 9,10 and -5 9,11 can now enable the development of MP-sparing aggrecanase inhibitors by allowing direct comparison of the active site of ADAMTS-4/-5 with MMPs and ADAMs and applying the structure-based drug design approach. Recently our group reported the mechanism of selectivity of a series of cis-1(S)2(R)-amino-2-indanol based compounds by generating the crystal structures of these molecules with the catalytic domain of ADAMTS-5.…”