Crystallization and preliminary X-ray analysis of two density populations of feline calicivirus

Two density populations of full-size feline calicivirus (FCV), the intact infectious particles (P_H) and the empty capsids (P_L), have been crystallized using the hanging-drop method. Exposed to high-intensity synchrotron radiation, P_H and P_L crystals were shown to diffract X-rays to about 3.0 and 5.5 Å resolution, respectively. The P_H crystal belongs to an orthorhombic crystal system with unit-cell dimensions a = 889.0, b = 995.0, c = 436.6 Å. Based on the V_M value (3.4 Å³ Da^-l), it was estimated that one crystallographic asymmetric unit of P_H crystals contains the unique content of an entire virus particle, not necessarily from the same particle. This implies the presence of 60-fold non-crystallographic redundancy. The particle orientation was obtained from a locked rotation function.