The 420 kDa hemolymph clottable protein has been purified from the California spiny lobster Panulirus interrruptus and crystallized in both monoclinic and orthorhombic space groups. Complete data sets have been collected from the two crystal forms to a maximum resolution of 3.9 and 3.2 A, respectively. The monoclinic crystals exhibit unusual noncrystallographic symmetry with pseudo-ninefold rotational symmetry generated from three dimers per asymmetric unit. The orthorhombic crystals have a single dimer per asymmetric unit. Attempts to phase the data are currently under way.
