The role of coiled-coil alpha-helices and disulfide bonds in the assembly and stabilization of cartilage matrix protein subunits. A mutational analysis

J Biol Chem. 1995 Sep 29;270(39):23150-4. doi: 10.1074/jbc.270.39.23150.


Cartilage matrix protein (CMP) exists as a disulfide-bonded homotrimer in the matrix of cartilage. Each monomer consists of two CMP-A domains that are separated by an epidermal growth factor-like domain. A heptad repeat-containing tail makes up the carboxyl-terminal domain of the protein. The secreted form of CMP contains 12 cysteine residues numbered C1 through C12. Two of these are in each of the CMP-A domains, six are in the epidermal growth factor-like domain, and two are in the heptad repeat-containing tail. Two major categories of mutant CMPs were generated to analyze the oligomerization process of CMP: a mini-CMP and a heptadless full-length CMP. The mini-CMP consists of the CMP-A2 domain and the heptad repeat-containing tail. In addition, a number of mutations affecting C9 through C12 were generated within the full-length, the mini-, and the heptad-less CMPs. The mutational analysis indicates that the heptad repeats are necessary for the initiation of CMP trimerization and that the two cysteines in the heptad repeat-containing tail are both necessary and sufficient to form intermolecular disulfide bonds in either full-length or mini-CMP. The two cysteines within a CMP-A domain form an intradomain disulfide bond.

Publication types

  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Amino Acid Sequence
  • Animals
  • Base Sequence
  • Cartilage
  • Cell Line
  • Chickens
  • Chlorocebus aethiops
  • Cysteine*
  • DNA Mutational Analysis
  • DNA Primers
  • Disulfides
  • Drug Stability
  • Epidermal Growth Factor / chemistry
  • Extracellular Matrix Proteins*
  • Glycoproteins / biosynthesis
  • Glycoproteins / chemistry*
  • Glycoproteins / genetics
  • Macromolecular Substances
  • Matrilin Proteins
  • Molecular Sequence Data
  • Mutagenesis, Site-Directed
  • Polymerase Chain Reaction
  • Protein Structure, Secondary*
  • Recombinant Proteins / biosynthesis
  • Recombinant Proteins / chemistry
  • Transfection


  • DNA Primers
  • Disulfides
  • Extracellular Matrix Proteins
  • Glycoproteins
  • Macromolecular Substances
  • Matrilin Proteins
  • Recombinant Proteins
  • Epidermal Growth Factor
  • Cysteine