@article{180391,
  keywords = {Animals, Protein Conformation, Base Sequence, Kinetics, Humans, Recombinant Proteins, Molecular Sequence Data, Molecular Structure, Caenorhabditis elegans, Extracellular Space, Species Specificity, Amino Acid Sequence, Sequence Homology, Amino Acid, Peptide Fragments, Metalloendopeptidases, Osteonectin, Collagen, DNA Primers, Polymerase Chain Reaction, Helminth Proteins},
  author = {Maurer and Sasaki and Mann and G{\"o}hring and Schwarzbauer and Timpl},
  title = {Structural and functional characterization of the extracellular calcium-binding protein BM-40/secreted protein, acidic, rich in cysteine/osteonectin from the nematode Caenorhabditis elegans},
  abstract = {<p>Caenorhabditis elegans BM-40 (positions 19-264) and its extracellular calcium-binding domain (positions 139-264) were obtained in recombinant form from human kidney cells using an episomal expression vector. The purified proteins showed single bands of 33 kDa [BM-40-(19-264)-peptide] or 14 kDa [BM-40-(139-264)-peptide] on electrophoresis, contained internal disulfide bonds and a helices and were relatively resistant to matrix metalloproteinases. Hexosamine analysis indicated substitution by one N-linked and two O-linked oligosaccharides and recombinant BM-40 was indistinguishable in its immunological epitopes from nematode tissue-derived BM-40, suggesting that it was obtained in native form. Both recombinant C. elegans proteins showed a distinct binding activity for human collagens I and IV in solid-phase and surface-plasmon-resonance assays with an affinity (Kd = 1-2 microM), comparable to that of mammalian BM-40. However, calcium-binding studies revealed only a low-affinity site (Kd = 6.2 mM) and failed to show the characteristic conformational change upon addition of EDTA. These and a few other differences are apparently due to two extra disulfide bonds and two deletions/insertions in C. elegans BM-40 and can be partly interpreted from the X-ray structure of a large part of human BM-40. The immunological assays available and the predictions of the location of the collagen-binding epitope should facilitate a molecular and genetic approach to understand the function of BM-40 in the development of C. elegans.</p>
},
  year = {1997},
  journal = {Eur J Biochem},
  volume = {248},
  pages = {209-16},
  month = {08/1997},
  issn = {0014-2956},
  doi = {10.1111/j.1432-1033.1997.t01-1-00209.x},
  language = {eng},
}