Abstract
Interstitial collagen is degraded by members of the matrix metalloproteinase (MMP) family, including MMP-1. Previous work has shown that the region of MMP-1 coded for by exon 5 is implicated both in substrate specificity and inhibitor selectivity. We have constructed a chimeric enzyme, the exon 5 chimera, consisting primarily of MMP-1, with the region coded for by exon 5 replaced with the equivalent region of MMP-3, a noncollagenolytic MMP. Unlike MMP-3, the exon 5 chimera is capable of cleaving type I collagen, but the activity is only 2.2% of trypsin-activated MMP-1. 'Superactivation' of the chimera has no discernible effect, suggesting that the salt bridge formed in 'superactive' MMP-1 is not present. The kinetics for exon 5 chimera cleavage of two synthetic substrates display an MMP-3 phenotype, however, cleavage of gelatin is slightly impaired as compared to the parent enzymes. The K-iapp values for the exon 5 chimera complexed with synthetic inhibitors and N-terminal TIMP-2 also show a more MMP-3-like behaviour. However, the k(on) values for N-terminal TIMP-1 and N-terminal TIMP-2 are more comparable to those for MMP-1. These data show that the region of MMP-1 coded for by exon 5 is involved in both substrate specificity and inhibitor selectivity and the structural basis for our findings is discussed.
| Original language | English |
|---|---|
| Pages (from-to) | 1888-1896 |
| Number of pages | 9 |
| Journal | European Journal of Biochemistry |
| Volume | 268 |
| Issue number | 6 |
| Publication status | Published - Mar 2001 |
Keywords
- MMP-1
- MMP-3
- collagenolysis
- inhibitor
- TIMP
- HUMAN NEUTROPHIL COLLAGENASE
- C-TERMINAL DOMAIN
- CATALYTIC DOMAIN
- MATRIX METALLOPROTEINASES
- COLLAGENOLYTIC ACTIVITY
- SYNOVIAL COLLAGENASE
- CRYSTAL-STRUCTURE
- STROMELYSIN
- ACTIVATION
- EXPRESSION