Biomedical subjects

Robert Visse

Publications and source records attributed to Robert Visse.

6 recordsLinked to original sources

PubMed2006

The roles of substrate thermal stability and P2 and P1' subsite identity on matrix metalloproteinase triple-helical peptidase activity and collagen specificity.

The hydrolysis of collagen (collagenolysis) is one of the committed steps in extracellular matrix turnover. Within the matrix metalloproteinase (MMP) family distinct preferences for collagen types are seen. The substrate determinants that may guide these specificities are unknown. In this study, we have utilized 12 triple-helical substrates in combination with 10 MMPs to better define the contributions of substrate sequence and thermal stability toward triple helicase activity and collagen specificity. In general, MMP-13 was found to be distinct from MMP-8 and MT1-MMP(Delta279-523), in that enhanced substrate thermal stability has only a modest effect on activity, regardless of sequence. This result correlates to the unique collagen specificity of MMP-13 compared with MMP-8 and MT1-MMP, in that MMP-13 hydrolyzes type II collagen efficiently, whereas MMP-8 and MT1-MMP are similar in their preference for type I collagen. In turn, MMP-1 was the least efficient of the collagenolytic MMPs at processing increasingly thermal stable triple helices and thus favors type III collagen, which has a relatively flexible cleavage site. Gelatinases (MMP-2 and MMP-9(Delta444-707)) appear incapable of processing more stable helices and are thus mechanistically distinct from collagenolytic MMPs. The collagen specificity of MMPs appears to be based on a combination of substrate sequence and thermal stability. Analysis of the hydrolysis of triple-helical peptides by an MMP mutant indicated that Tyr(210) functions in triple helix binding and hydrolysis, but not in processing triple helices of increasing thermal stabilities. Further exploration of MMP active sites and exosites, in combination with substrate conformation, may prove valuable for additional dissection of collagenolysis and yield information useful in the design of more selective MMP inhibitors.

Amino Acid Sequence↗

PubMed2006

Crystal structure of an active form of human MMP-1.

The extracellular matrix is a dynamic environment that constantly undergoes remodelling and degradation during vital physiological processes such as angiogenesis, wound healing, and development. Unbalanced extracellular matrix breakdown is associated with many diseases such as arthritis, cancer and fibrosis. Interstitial collagen is degraded by matrix metalloproteinases with collagenolytic activity by MMP-1, MMP-8 and MMP-13, collectively known as the collagenases. Matrix metalloproteinase 1 (MMP-1) plays a pivotal role in degradation of interstitial collagen types I, II, and III. Here, we report the crystal structure of the active form of human MMP-1 at 2.67 A resolution. This is the first MMP-1 structure that is free of inhibitor and a water molecule essential for peptide hydrolysis is observed coordinated with the active site zinc. Comparing this structure with the human proMMP-1 shows significant structural differences, mainly in the relative orientation of the hemopexin domain, between the pro form and active form of the human enzyme.

Animals↗

PubMed2006

Structure and function of matrix metalloproteinases and TIMPs.

Matrix metalloproteinases (MMPs), also called matrixins, function in the extracellular environment of cells and degrade both matrix and non-matrix proteins. They play central roles in morphogenesis, wound healing, tissue repair and remodelling in response to injury, e.g. after myocardial infarction, and in progression of diseases such as atheroma, arthritis, cancer and chronic tissue ulcers. They are multi-domain proteins and their activities are regulated by tissue inhibitors of metalloproteinases (TIMPs). This review introduces the members of the MMP family and discusses their domain structure and function, proenyme activation, the mechanism of inhibition by TIMPs and their significance in physiology and pathology.

Animals↗

PubMed2004

X-ray structure of human proMMP-1: new insights into procollagenase activation and collagen binding.

Vertebrate collagenases, members of the matrix metalloproteinase (MMP) family, initiate interstitial fibrillar collagen breakdown. It is essential in many biological processes, and unbalanced collagenolysis is associated with diseases such as arthritis, cancer, atherosclerosis, aneurysm, and fibrosis. These metalloproteinases are secreted from the cell as inactive precursors, procollagenases (proMMPs). To gain insights into the structural basis of their activation mechanisms and collagen binding, we have crystallized recombinant human proMMP-1 and determined its structure to 2.2 A resolution. The catalytic metalloproteinase domain and the C-terminal hemopexin (Hpx) domain show the classical MMP-fold, but the structure has revealed new features in surface loops and domain interaction. The prodomain is formed by a three-helix bundle and gives insight into the stepwise activation mechanism of proMMP-1. The prodomain interacts with the Hpx domain, which affects the position of the Hpx domain relative to the catalytic domain. This interaction results in a "closed" configuration of proMMP-1 in contrast to the "open" configuration observed previously for the structure of active MMP-1. This is the first evidence of mobility of the Hpx domain in relation to the catalytic domain, providing an important clue toward the understanding of the collagenase-collagen interaction and subsequent collagenolysis.

Amino Acid Sequence↗

PubMed2004

Collagenase unwinds triple-helical collagen prior to peptide bond hydrolysis.

Breakdown of triple-helical interstitial collagens is essential in embryonic development, organ morphogenesis and tissue remodelling and repair. Aberrant collagenolysis may result in diseases such as arthritis, cancer, atherosclerosis, aneurysm and fibrosis. In vertebrates, it is initiated by collagenases belonging to the matrix metalloproteinase (MMP) family. The three-dimensional structure of a prototypic collagenase, MMP-1, indicates that the substrate-binding site of the enzyme is too narrow to accommodate triple-helical collagen. Here we report that collagenases bind and locally unwind the triple-helical structure before hydrolyzing the peptide bonds. Mutation of the catalytically essential residue Glu200 of MMP-1 to Ala resulted in a catalytically inactive enzyme, but in its presence noncollagenolytic proteinases digested collagen into typical 3/4 and 1/4 fragments, indicating that the MMP-1(E200A) mutant unwinds the triple-helical collagen. The study also shows that MMP-1 preferentially interacts with the alpha2(I) chain of type I collagen and cleaves the three alpha chains in succession. Our results throw light on the basic mechanisms that control a wide range of biological and pathological processes associated with tissue remodelling.

Amino Acid Sequence↗

PubMed2003

Matrix metalloproteinases and tissue inhibitors of metalloproteinases: structure, function, and biochemistry.

Matrix metalloproteinases (MMPs), also designated matrixins, hydrolyze components of the extracellular matrix. These proteinases play a central role in many biological processes, such as embryogenesis, normal tissue remodeling, wound healing, and angiogenesis, and in diseases such as atheroma, arthritis, cancer, and tissue ulceration. Currently 23 MMP genes have been identified in humans, and most are multidomain proteins. This review describes the members of the matrixin family and discusses substrate specificity, domain structure and function, the activation of proMMPs, the regulation of matrixin activity by tissue inhibitors of metalloproteinases, and their pathophysiological implication.

Chromosome Mapping↗