No abstract

Matrix metalloproteinase-13 (MMP-13) has been implicated to play a key role in the pathology of osteoarthritis. On the basis of X-ray crystallography, we designed a series of potent MMP-13 selective inhibitors optimized to occupy the distinct deep S1' pocket including an adjacent branch. Among them, carboxylic acid inhibitor 21k exhibited excellent potency and selectivity for MMP-13 over other MMPs. An effort to convert compound 21k to the mono sodium salt 38 was promising in all animal species studied. Moreover, no overt toxicity was observed in a preliminary repeat dose oral toxicity study of compound 21k in rats. A single oral dose of compound 38 significantly reduced degradation products (CTX-II) released from articular cartilage into the joint cavity in a rat MIA model in vivo. In this article, we report the discovery of highly potent, selective, and orally bioavailable MMP-13 inhibitors as well as their detailed structure-activity data.

The structure of orthorhombic hen egg-white lysozyme (HEWL) crystallized at 310 K has been refined at 1.7 A resolution. Large displacements of the side-chain atoms with respect to the tetragonal structure were observed in many places, in contrast to small displacements of the main-chain atoms. A chloride-ion binding site was observed at an interface of two molecules, but at a different position to the binding site in the tetragonal form. The analysis of intermolecular contacts in the crystal has shown the presence of three independent intermolecular contacts which are called macrobonds A, B and C. Arginine side chains are frequently involved in these macrobonds, suggesting that the high frequency of this residue in HEWL may be a possible reason for the multiple polymorphs of this protein. The crystal forms were determined using a light-reflecting device on a four-circle diffractometer. Correlations between crystal forms and the three-dimensional macrobond networks were interpreted in terms of their components in various crystallographic planes, making use of approximate strengths of hydrogen-bond and van der Waals interatomic forces.