title: The fibronectin-like domain is required for the type V and XI collagenolytic activity of gelatinase B.
abstract: Gelatinase B (matrix metalloproteinase-9) is able to degrade several extracellular matrix proteins, including gelatin, elastin, and collagen types IV, V, XI, and XIV. This enzyme contains a "fibronectin-like" domain which is composed of three tandem copies of a fibronectin type 2 homology unit inserted into its catalytic domain. We have studied the involvement of this domain in the substrate specificity of gelatinase B by expressing a mutant of the enzyme, in Escherichia coli, in which this domain has been deleted. This mutant enzyme retained its ability to cleave the peptide substrate Mca-PLGL(Dpa)AR-NH2, possessing K(m) and kcat values similar to those of the wild-type enzyme. In addition, the NH2-terminal, 14-kDa, inhibitory domain of recombinant tissue inhibitor of metalloproteinase-2 was able to inhibit the mutant and the wild-type enzymes with the same potency. The mutant's gelatinolytic activity was also retained but reduced in comparison to that of the wild-type enzyme. However, contrary to the wild-type enzyme, the mutant was not able to digest or bind fibrillar collagen types V and XI. These data indicate that the fibronectin-like domain of gelatinase B is an important determinant of the enzyme's fibrillar collagen substrate specificity. It allows the enzyme to bind to and cleave collagen types V and XI, events which are thought to be involved in several normal physiological and pathological processes such as metastasis and arthritis.
authors.affiliation: Department of Biochemistry, University of Tennessee, Memphis 38163, USA.
authors.forename: T J
authors.initials: TJ
authors.lastname: O'Farrell
authors.forename: T
authors.initials: T
authors.lastname: Pourmotabbed
mesh_terms: D003094:Collagen / Q000378:metabolism*; D017364:Collagenases / Q000235:genetics / Q000302:isolation & purification / Q000378:metabolism*; D005353:Fibronectins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D006868:Hydrolysis; D020780:Matrix Metalloproteinase 9; D011485:Protein Binding; D017434:Protein Structure, Tertiary; D011994:Recombinant Proteins / Q000302:isolation & purification / Q000378:metabolism
chemical_list: D005353:Fibronectins; D011994:Recombinant Proteins; D003094:Collagen; D017364:Collagenases; D020780:Matrix Metalloproteinase 9