matrix metalloproteinase-1; matrixin-1; interstitial collagenase; fibroblast collagenase (MMP1, CLG)

^[1]^[2]

Function

cleaves collagens of types 1, 2, & 3 at one site in the helical domain
also cleaves collagens of types 7 & 10
in case of HIV infection, interacts & cleaves the secreted viral Tat protein, leading to a decrease in neuronal Tat's mediated neurotoxicity
can be activated without removal of the activation peptide
undergoes autolytic cleavage to two major forms (22 kD & 27 kD (a minor form (25 kD) is the glycosylated form of the 22 kD form)
the 27 kD form has no activity while the 22/25 kD form can act as activator for collagenase
cleavage of the triple helix of collagen at about 3/4 of the length of the molecule from the N-terminus, at 775-Gly-|-Ile-776 in the alpha-1(I) chain
cleaves synthetic substrates & alpha-macroglobulins at bonds where P1' is a hydrophobic residue

two distinct domains in this protein
- catalytic N-terminal
- C-terminal, involved in substrate specificity & in binding TIMP (tissue inhibitor of metalloproteinases)
conserved cysteine present in the cysteine-switch motif binds the catalytic Zn+2, thus inhibiting the enzyme; dissociation of the cysteine from the Zn+2 upon the activation-peptide release activates the enzyme
belongs to the peptidase M10A family
contains 4 hemopexin-like domains