Matrix Metalloproteinase-1 Takes Advantage of the Induced Fit Mechanism To Cleave the Triple-Helical Type I Collagen Molecule

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• 作者：Thomas J. O'Farrell ; Rong Guo ; Hisashi Hasegawa ; Tayebeh Pourmotabbed
• 刊名：Biochemistry
• 出版年：2006
• 出版时间：December 26, 2006
• 年：2006
• 卷：45
• 期：51
• 页码：15411 - 15418
• 全文大小：181K
• 年卷期：v.45,no.51(December 26, 2006)
• ISSN：1520-4995

文摘

The collagenases are members of the matrix metalloproteinase family (MMP) that degradenative triple-helical type I collagen. To understand the mechanism by which these enzymes recognizeand cleave this substrate, we studied the substrate specificity of a modified form of MMP-1 (FC) inwhich its active site region (amino acids 212-254) had been replaced with that of MMP-9 (amino acids395-437). Although this substitution increased the activity of the enzyme toward gelatin and the peptidesubstrate Mca-PLGL(Dpa)AR-NH₂ by ~3- and ~11-fold, respectively, it decreased the type I collagenolyticactivity of the enzyme to 0.13%. The replacement of Gly²³³, the only amino acid in this region of FC thatis conserved in all collagenase family members, with the corresponding Glu residue in MMP-9 resultedin a substantial decrease in the type I collagenolytic activity of the enzyme without affecting its generalproteolytic activities. The kinetic parameters of the FC/G233E mutant for the collagen substrate weresimilar to those of the chimeric enzyme. In addition, substituting Gly²³³ for Glu in the chimera increasedthe collagenolytic activity of the enzyme by 12-fold. Interestingly, replacing Glu⁴¹⁵ in MMP-9 with Gly,its corresponding residue in FC, endowed the enzyme with type I collagenolytic activity. The catalyticactivity of the MMP-9 mutant toward triple-helical type I collagen was 2-fold higher than that of thecollagenase chimera. These data in conjunction with the X-ray crystal structure of FC indicate that Gly²³³provides the flexibility necessary for the enzyme active site to change conformation upon substrate binding.The flexibility provided by the Gly residue is essential for type I collagenolytic activity.