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THE CRYSTAL STRUCTURE OF HUMAN PROCATHEPSIN KTHE CRYSTAL STRUCTURE OF HUMAN PROCATHEPSIN K
Structural highlights
DiseaseCATK_HUMAN Defects in CTSK are the cause of pycnodysostosis (PKND) [MIM:265800. PKND is an autosomal recessive osteochondrodysplasia characterized by osteosclerosis and short stature.[1] [2] [3] [4] FunctionCATK_HUMAN Closely involved in osteoclastic bone resorption and may participate partially in the disorder of bone remodeling. Displays potent endoprotease activity against fibrinogen at acid pH. May play an important role in extracellular matrix degradation. Evolutionary ConservationCheck, as determined by ConSurfDB. You may read the explanation of the method and the full data available from ConSurf. Publication Abstract from PubMedCathepsin K is a cysteine protease present in human osteoclasts that plays an important role in bone resorption. Cathepsin K is synthesized as an inactive proenzyme and activated under conditions of low pH. Autoproteolytic processing of the N-terminal 99 amino acid propeptide produces the active, mature form of cathepsin K. It is presumed that the activation of procathepsin K in vivo occurs in the bone resorption pit, which has a low-pH environment. We have determined the structure of human procathepsin K at 2.8 A resolution. The structure of the mature enzyme domain within procathepsin K is virtually identical to that of mature cathepsin K. The fold of the propeptide of procathepsin K is similar to that observed in procathepsins B and L despite differences in length and sequence. A portion of the propeptide occupies the active site cleft of cathepsin K. Hydrophobic interactions, salt bridges, and hydrogen-bonding interactions are observed in the structure of the propeptide and between the propeptide and the mature enzyme of procathepsin K. These interactions suggest an explanation for the stability of the proenzyme. The structure of procathepsin K contributes to an understanding of the molecular basis of inhibition by the propeptide portion of the molecule and activation of this important member of the cysteine protease family. The crystal structure of human procathepsin K.,LaLonde JM, Zhao B, Janson CA, D'Alessio KJ, McQueney MS, Orsini MJ, Debouck CM, Smith WW Biochemistry. 1999 Jan 19;38(3):862-9. PMID:9893980[5] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. See AlsoReferences
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