The Structural Basis for the Elastolytic Activity of the 92-kDa and 72-kDa Gelatinases

Abstract

Several matrix metalloproteinases, including the 92-kDa and 72-kDa gelatinases, macrophage metalloelastase (MME), and matrilysin degrade insoluble elastin. Because elastolytically active MME and matrilysin consist only of a catalytic domain (CD), we speculated that the homologous CDs of the 92-kDa and 72-kDa gelatinases would confer their elastolytic activities. In contrast to the MME CD, the 92 and 72 CDs expressed in Escherichia coli (lacking the internal fibronectin type II-like repeats) had no elastase activity, although both were gelatinolytic and cleaved a thiopeptolide substrate at rates comparable to the full-length gelatinases. Elastin is an extracellular matrix protein composed of highly cross-linked, hydrophobic tropoelastin monomers which provides resilience to elastic fibers. The hydrophobicity and extensive cross-linking of tropoelastin monomers result in an insoluble elastic fiber which is highly resistant to proteolysis (1). Thus, under normal physiologic conditions, elastin undergoes minimal turnover (2). However, certain pathologic situations, including pulmonary emphysema (3) and abdominal aortic aneurysm (4), are characterized by proteolytic destruction of elastic fibers. The involvement of serine proteases in such pathologies has long been suspected. More recently, participation of cysteine proteinases (5) and matrix metalloproteinases (MMPs, 1 6 -8) in these diseases has been proposed. The MMPs comprise a gene family that collectively is capable of degrading all components of extracellular matrix in physiologic and pathologic states (9, 10). As presently recognized, this family consists of fibroblast (11), neutrophil (12), and breast carcinoma-derived (13) collagenases, three stromelysins, 92-kDa and 72-kDa gelatinases, macrophage metalloelastase (MME, MMP-12), matrilysin, and a recently described 66-kDa membrane-type metalloproteinase (14). These enzymes are organized into homologous structural domains, with some differences in domain composition and number. All members share a zymogen domain, containing a conserved PRCGXPD motif involved in enzyme latency, and a zinc-binding CD. Most members also contain a hemopexin-like domain at their C terminus, the exception being matrilysin, which lacks this domain completely. Unique to the 72-kDa and 92-kDa gelatinases is an additional domain composed of three fibronectin type II-like repeats inserted in tandem within the zinc-binding CD. The 92-kDa gelatinase also contains an ␣2(V) collagen-like domain not found in any of the other family members.The issue of substrate specificity has received considerable attention recently in MMP biology. The determinants which confer substrate specificity to these enzymes appear to be localized within discrete structural domains. For example, the ability of the collagenases to degrade triple-helical collagen requires the presence of the C-terminal hemopexin-like domain (15)(16)(17). In contrast, the stromelysins degrade a variety of substrates in a manner which is independent of the C-terminal hemopexin-like dom...

Matrix metalloproteinase 9 gene polymorphisms are associated with a multiple family history of gastric cancer

“…MMP9 R279Q polymorphism leads to an amino acid exchange (arginine to glycine) in the fibronectin type II domain of the catalytic domain that plays an important role in substrate binding [30,31], suggesting that MMP-9 activity levels may be higher in subjects with the 279QQ genotype [30]. The T allele of MMP9 -1562 is associated with elevated MMP-9 plasma concentration [32] in accordance with the increased promoter activity of the -1562T allele [33].…”

Involvement of Fibronectin Type II Repeats in the Efficient Inhibition of Gelatinases A and B by Long-chain Unsaturated Fatty Acids

“…The kringles mediate the binding of multidomain proteins to other proteins. The presence of FN-II modules allows gelatinases A and B to bind and degrade insoluble elastin, a highly hydrophobic extracellular matrix macromolecule (16,39). Binding of long-chain fatty acids to kringles was found to modulate plasmin activity toward both synthetic substrate and fibrinogen (20,21).…”

Gelatin-binding Region of Human Matrix Metalloproteinase-2

“…We have reported elsewhere (15) on the solution structure and ligandbinding surface of the second FII module (COL-2) (see Fig. 1a) of MMP-2, which was mapped on the basis of 1 H and 15 N NMR perturbations induced by the synthetic gelatin-like octadecapeptide (Pro-Pro-Gly) 6 , henceforth denoted as PPG6, a mimic of gelatin. Here, we present the NMR solution structure of the third FII module (COL-3) (see Fig.…”

“…Section 1734 solely to indicate this fact. 1 The abbreviations used are: MMP, matrix metalloproteinase; ECM, extracellular matrix; FII, fibronectin type II; TOCSY, total correlation spectroscopy; NOESY, nuclear Overhauser effect correlation spectroscopy; HSQC, heteronuclear single-quantum correlation spectroscopy; X-NOE, heteronuclear nuclear Overhauser effect; PPG6, synthetic peptide (Pro-Pro-Gly) 6 ; PPG12, synthetic peptide (Pro-Pro-Gly) 12 ; p33-42, acetyl-Pro-Ile-Ile-Lys-Phe-Pro-Gly-Asp-Val-Ala-amide (synthetic peptide corresponding to residues 33-42 of human pro-MMP-2).…”