The C-terminal domain of matrilin-2 assembles into a three-stranded alpha-helical coiled coil.
Matrilin-2 is a member of von Willebrand factor A containing extracellular matrix proteins in which the cDNA-derived sequence shows similar domain organization to cartilage matrix protein/matrilin-1, but information on the protein structure is limited. Here we studied the oligomerization potential of a synthetic peptide NH2-ENLILFQNVANEEVRKLTQRLEEMTQRMEALENRLKYR-COOH corresponding to the C-terminal sequence of mouse matrilin-2. The central portion of this sequence shows a periodicity of hydrophobic residues occupying positions a and d of a heptad pattern (abcdefg)n, which is characteristic for alpha-helical coiled-coil proteins. Circular dichroism spectroscopy revealed a high alpha-helical content, and the shape of the spectra is indicative for a coiled-coil conformation. Chemical cross-linking and size exclusion chromatography suggest a homotrimeric configuration. Thermal denaturation in benign buffer shows a single cooperative transition with DeltaH0 = -375 kJ/mol. Melting temperatures Tm varied from 38 to 51 degreesC within a concentration range of 10 to 85 microM, which is about 35 degreesC lower than determined for a peptide corresponding to the C-terminal domain of matrilin-1. The data suggest that despite the low sequence identity within this region, matrilin-2 will form a homotrimer as matrilin-1 does.
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Department of Biological Science, Rutgers-The State University of New Jersey, Piscataway, New Jersey 08855, USA.
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D000595:Amino Acid Sequence; D000818:Animals; D002942:Circular Dichroism; D003432:Cross-Linking Reagents / Q000378:metabolism; D016326:Extracellular Matrix Proteins / Q000737:chemistry*; D006023:Glycoproteins / Q000737:chemistry*; D064235:Matrilin Proteins; D051379:Mice; D008969:Molecular Sequence Data; D010446:Peptide Fragments / Q000737:chemistry; D011487:Protein Conformation; D011489:Protein Denaturation; D017433:Protein Structure, Secondary; D013388:Succinimides / Q000378:metabolism; D013696:Temperature; D013816:Thermodynamics
D003432:Cross-Linking Reagents; D016326:Extracellular Matrix Proteins; D006023:Glycoproteins; C577540:Matn1 protein, mouse; C577542:Matn2 protein, mouse; D064235:Matrilin Proteins; D010446:Peptide Fragments; D013388:Succinimides; C096464:disuccinimidyl glutarate