ISSN:
1420-9071
Keywords:
Key words. Calcium binding; collagen affinity; extracellular matrix; kinetic analysis; matrix metalloproteinase.
Source:
Springer Online Journal Archives 1860-2000
Topics:
Biology
,
Medicine
Notes:
Abstract. The calcium-binding extracellular matrix protein BM-40 was obtained as a mouse cDNA product from a stably transfected kidney cell clone. Electrophoresis and N-terminal sequence analysis demonstrated absence of the proteolytic processing previously observed for a mouse tumour-derived BM-40. Yet the two forms of BM-40 were very similar in their CD spectra, their calcium-dependent change in α helix content and their immunological epitopes. In surface plasmon resonance assays, recombinant mouse BM-40 showed distinct binding to the triple-helical domains of collagens I, II, III, IV and V with Kd=1–4 μM but no binding to collagen VI. These interactions were abolished in the presence of EDTA. Tissue-derived mouse BM-40, however, bound collagens I and IV with Kd=0.1–0.2 μM. Activation of collagen binding to give a similar Kd could be achieved for recombinant mouse BM-40 by treatment with the matrix metalloproteinase collagenase-3. The major cleavage site was located in helix C of the extracellular calcium-binding module of BM-40 and other less prominent cleavages occurred close to the N-terminus. The sensitive helix C site was just one residue away from that sensitive to endogenous tissue proteolysis, suggesting that cleavage could be a physiological mechanism to modulate collagen binding.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1007/s000180050059
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