Ranasmurfin, a previously uncharacterized approximately 13 kDa blue protein 
found in the nests of the frog Polypedates leucomystax, has been purified and 
crystallized. The crystals are an intense blue colour and diffract to 1.51 A 
with P2(1) symmetry and unit-cell parameters a = 40.9, b = 59.9, c = 45.0 A, 
beta = 93.3 degrees . Self-rotation function analysis indicates the presence of 
a dimer in the asymmetric unit. Biochemical data suggest that the blue colour of 
the protein is related to dimer formation. Sequence data for the protein are 
incomplete, but thus far have identified no model for molecular replacement. A 
fluorescence scan shows a peak at 9.676 keV, indicating that the protein binds 
zinc and suggesting a route for structure solution.