The explicitly polarized force field model is indispensable in the simulation of protein crystal due to its particular electrostatic environment which is different from that in water solution.The polarized protein-specific charge(PPC)has shown important priorities for the study of protein-ligand binding and protein folding.However,the applicability of PPC in the simulation of protein crystal is yet to be examined.Two 250 ns molecular simulations were carried out to study the structure and dynamics of crystal toxin protein Ⅱ from the scorpion Androctonus australis Hector employing PPC as well as the standard AMBER99SB force field to investigate the effect of electrostatic polarization on the crystal stability.Our simulation results showed that under PPC,the monomer in the subunit cell and the lattice in the supercell were more stable with much smaller RMSDs and the lattice atomic fluctuations were also better in line with the crystallographic B-factors.Most of the interactions at interfaces in the X-ray structure were well preserved,underscoring the important effect of polarization on maintaining the crystal stability.However,our results also showed that the hydrogen bond between Asp53 and Gln37 and the cation-л interaction between Arg56 and His64 were not as stable,indicating that further optimization of force field with van der Waals interaction parameters is desired.