NOVEL FOLD AND PUTATIVE RECEPTOR-BINDING SITE OF GRANULOCYTE-MACROPHAGE COLONY-STIMULATING FACTOR

Granulocyte-macrophage colony-stimulating factor (GM-CSF) stimulates the development of and the cytotoxic activity of white blood cells. Recombinant human GM-CSF has proven useful in the treatment of blood disorders. The structure of GM-CSF, which was determined at 2.4 angstrom resolution by x-ray crystallography, has a novel fold combining a two-stranded antiparallel-beta-sheet with an open bundle of four a helices. Residues implicated in receptor recognition, which are distant in the primary sequence, are on adjacent alpha-helices in the folded protein. A working model for the receptor binding site is presented.