PREDICTION AND COMPARISON OF SECONDARY STRUCTURES AND SURFACE PROBABILITIES OF CAPSID PROTEINS OF REFERENCE STRAINS OF THREE TYPE POLIOVIRUSES WITH COMPUTER
Results o.f microcomputer analysis are reported on the prediction and comparison of secondary structures and surface probabilities of the ca.psid proteins of 6 reference strains of the three type of polioviruses and on the secondary structure basis for antigenic sites on the surface of capsid and for neurovirulent attenuation. The results showed: ( 1 ) there are some similarities in the secondary structure of VP1, VP2 and VP3 with 8 or more sheets in each of the 3 proteins, ( 2 ) the 5 peptides capable of priming immune system in rabbit for an IgG response are formed by characteristic turn structures and it is speculated that only a turn can be an antigenic determinant and the increase, decrease, translocation of turn or residue substitution in the turn may be the structural basis for antigenic change of poliovi-rus; ( 3 ) attenuation does not basically cause changes of secondary struc-turse of viral proteins, but cause changes of hydrophilic surface probabilities of some regions of the viral proteins; (4) according to surface probabilities, intratypic-specific regions and intertypic specific regions are identified. These results are of importance in designing synthetic vaccine and re-combinant vaccine against poliomyelitis.