1. WILHELM, S.M., COLLIER, I.E., MARMER, B.L., EISEN, A.Z., GRANT, G.A.
AND GOLDBERG, G.I.
SV40-transformed human lung fibroblasts secrete a 92kDa type IV
collagenase which is identical to that secreted by normal human macrophages.
J.BIOL.CHEM. 264(29) 17213-17221 (1989).
2. LEPAGE, T. AND GACHE, C.
Early expression of a collagenase-like hatching enzyme gene in the sea
EMBO J. 9(9) 3003-3012 (1990).
Extracellular metalloproteases, such as collagenase and stromelysin, which
degrade the extracellular matrix, are known as matrixins. They are zinc-
dependent, calcium-activated proteases synthesised as inactive precursors
(zymogens), which are proteolytically cleaved to yield the active enzyme
[1,2]. All matrixins and related proteins possess 2 domains: an N-terminal
domain, and a zinc-binding active site domain. The N-terminal domain
peptide, cleaved during the activation step, includes a conserved PRCGVPDV
octapeptide, known as the cysteine switch, whose Cys residue chelates the
active site zinc atom, rendering the enzyme inactive. The active enzyme
degrades components of the extracellular matrix, playing a role in the
initial steps of tissue remodelling during morphogenesis, wound healing,
angiogenesis and tumour invasion [1,2].
MATRIXIN is a 5-element fingerprint that provides a signature for the
matrixins. The fingerprint was derived from an initial alignment of 5
sequences: motif 1 includes the N-terminal octapeptide encoded by PROSITE
pattern CYSTEINE_SWITCH (PS00546), and motifs 2-5 were drawn from conserved
regions in the active site domain - motif 4, which includes 2 His residues
and a catalytic Glu, encodes a characteristic zinc binding site (cf.
PROSITE pattern ZINC_PROTEASE (PS00142)). Two iterations on OWL22.1 were
required to reach convergence, at which point a true set comprising 30
sequences was identified. Ten partial matches were also found, 9 of
which are functionally-related secreted metalloproteases, and the tenth,
S11026, a procollagenase fragment.
An update on SPTR37_9f identified a true set of 82 sequences, and 13