Structure of C-terminal fragment of merozoite surface protein-1 from Plasmodium vivax determined by homology modeling and molecular dynamics refinement.

One current vaccine candidate against Plasmodium vivax targeting asexual blood stage is the major merozoite surface protein-1 of P. vivax (PvMSP-1). Vaccine trials with PvMSP-1(19) and PvMSP-1(33) have succeeded in protecting monkeys and a large proportion of individuals, naturally exposed to P. vivax transmission, develop specific antibodies to PvMSP-1(19). This study presents a model for the three-dimensional structure of the C-terminal 19kDa fragment of P. vivax MSP-1 determined by means of homology modeling and molecular dynamics refinement. The structure proved to be consistent with MSP-1(19) of known crystal or solution structures. The presence of a main binding pocket, well suited for protein-protein interactions, was determined by CASTp. Corrections reported to the sequence of PvMSP-1(19) Belem strain were also inspected. Our model is currently used as a basis to understand antibody interactions with PvMSP-1(19).