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The Three-Dimensional Structure Of Bovine Platelet Factor 4 At 3.0-Å Resolution, Robert St. Charles, Daniel A. Walz, Brian Fp Edwards

Biochemistry and Molecular Biology Faculty Publications

Platelet factor 4 (PF4), which is released by platelets during coagulation, binds very tightly to negatively charged oligosaccharides such as heparin. To date, six other proteins are known that are homologous in sequence with PF4 but have quite different functions. The structure of a tetramer of bovine PF4 complexed with one Ni(CN)42− molecule has been determined at 3.0 Å resolution and refined to an R factor of 0.28. The current model contains residues 24–85, no solvent, and one overall temperature factor. Residues 1–13, which carried an oligosaccharide chain, were removed with elastase to induce crystallization; residues 14–23 and presumably 86–88 …