Kashiwagi M, Tortorella M, Nagase H, Brew K
Department of Biochemistry and Molecular Biology, University of Miami School of Medicine, Miami, Florida 33101, USA.
J Biol Chem. 2001 Apr 20;276(16):12501-4. doi: 10.1074/jbc.C000848200. Epub 2001 Jan 23.
The proteoglycan aggrecan is an important major component of cartilage matrix that gives articular cartilage the ability to withstand compression. Increased breakdown of aggrecan is associated with the development of arthritis and is considered to be catalyzed by aggrecanases, members of the ADAM-TS family of metalloproteinases. Four endogenous tissue inhibitors of metalloproteinases (TIMPs) regulate the activities of functional matrix metalloproteinases (MMPs), enzymes that degrade most components of connective tissue, but no endogenous factors responsible for the regulation of aggrecanases have been found. We show here that the N-terminal inhibitory domain of TIMP-3, a member of the TIMP family that has functional properties distinct from other TIMPs, is a strong inhibitor of human aggrecanases 1 and 2, with K(i) values in the subnanomolar range. This truncated inhibitor, which lacks the C-terminal domain that is responsible for interactions with molecules other than active metalloproteinases, is produced at high yield by bacterial expression and folding from inclusion bodies. This provides a starting point for developing a biologically available aggrecanase inhibitor suitable for the treatment of arthritis.
蛋白聚糖聚集蛋白聚糖是软骨基质的一种重要主要成分，它赋予关节软骨承受压力的能力。聚集蛋白聚糖分解增加与关节炎的发展相关，并且被认为是由聚集蛋白聚糖酶催化的，聚集蛋白聚糖酶是金属蛋白酶ADAM-TS家族的成员。四种内源性金属蛋白酶组织抑制剂（TIMPs）调节功能性基质金属蛋白酶（MMPs）的活性，MMPs是降解结缔组织大多数成分的酶，但尚未发现负责调节聚集蛋白聚糖酶的内源性因子。我们在此表明，TIMP-3的N端抑制结构域是TIMP家族的成员，其功能特性与其他TIMPs不同，是人类聚集蛋白聚糖酶1和2的强效抑制剂，其抑制常数（K(i)）值在亚纳摩尔范围内。这种截短的抑制剂缺乏负责与活性金属蛋白酶以外的分子相互作用的C端结构域，通过细菌表达和从包涵体折叠可高产获得。这为开发适用于治疗关节炎的具有生物活性的聚集蛋白聚糖酶抑制剂提供了一个起点。
