Various diverse extracellular proteins possess Ca(2+)-binding epidermal growth factor (EGF)-like domains, the function of which remains uncertain. We have determined, at high resolution (1.5 A), the crystal structure of such a domain, from human clotting factor IX, as a complex with Ca2+ ...
Various diverse extracellular proteins possess Ca(2+)-binding epidermal growth factor (EGF)-like domains, the function of which remains uncertain. We have determined, at high resolution (1.5 A), the crystal structure of such a domain, from human clotting factor IX, as a complex with Ca2+. The Ca2+ ligands form a classic pentagonal bipyramid with six ligands contributed by one polypeptide chain and the seventh supplied by a neighboring EGF-like domain. The crystal structure identifies the role of Ca2+ in maintaining the conformation of the N-terminal region of the domain, but more importantly demonstrates that Ca2+ can directly mediate protein-protein contacts. The observed crystal packing of the domains provides a plausible model for the association of multiple tandemly linked EGF-like domains in proteins such as fibrillin-1, Notch, and protein S. This model is consistent with the known functional data and suggests a general biological role for these domains.
Related Citations:
Crystallization of a Calcium-Binding Egf-Like Domain Rao, Z., Handford, P., Mayhew, M., Knott, V., Brownlee, G.G., Stuart, D. (1995) Acta Crystallogr D Biol Crystallogr 51: 402
Organizational Affiliation:
Laboratory of Molecular Biophysics, University of Oxford, England.
Download Mendeley
