Properties of the extracellular calcium binding module of the proteoglycan testican.
The extracellular calcium-binding (EC) module of human testican (115 residues) was obtained in native form by recombinant production in mammalian cell culture and thus shown to represent an independently folding domain. This module showed a large loss in alpha-helix upon calcium depletion. Apparently only one of the two EF hands binds calcium, with a moderate affinity (Kd =68 microM) about 100-fold lower than in the homologous BM-40 protein. No clear evidence was obtained for collagen binding, indicating that EC modules found in different proteins may not share similar functions.
Kohfeldt
E
E
Max-Planck-Institut für Biochemie, Martinsried, Germany.
Maurer
P
P
Vannahme
C
C
Timpl
R
R
D000595:Amino Acid Sequence; D000818:Animals; D002118:Calcium / Q000378:metabolism*; D004797:Enzyme-Linked Immunosorbent Assay; D005822:Genetic Vectors / Q000235:genetics; D006801:Humans; D007106:Immune Sera; D008969:Molecular Sequence Data; D015676:Osteonectin / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D010957:Plasmids / Q000235:genetics; D011509:Proteoglycans / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism*; D011817:Rabbits; D011994:Recombinant Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D017384:Sequence Deletion; D017386:Sequence Homology, Amino Acid; D014961:X-Ray Diffraction
D007106:Immune Sera; D015676:Osteonectin; D011509:Proteoglycans; D011994:Recombinant Proteins; D002118:Calcium