Solution structure of a Plasmodium falciparum AMA-1/MSP 1 chimeric protein vaccine candidate (PfCP-2.9) for malaria.
BACKGROUND
The Plasmodium falciparum chimeric protein PfCP-2.9 is a promising asexual-stage malaria vaccine evaluated in clinical trials. This chimeric protein consists of two cysteine-rich domains: domain III of the apical membrane antigen 1 (AMA-1 [III]) and the C-terminal region of the merozoite surface protein 1 (MSP1-19). It has been reported that the fusion of these two antigens enhanced their immunogenicity and antibody-mediated inhibition of parasite growth in vitro.


METHODS
The 15N-labeled and 13C/15N-labeled PfCP-2.9 was produced in Pichia pastoris for nuclear magnetic resonance (NMR) structure analysis. The chemical shift assignments of PfCP-2.9 were compared with those previously reported for the individual domains (i.e., PfAMA-1(III) or PfMSP 1-19). The two-dimensional spectra and transverse relaxation rates (R2) of the PfMSP1-19 alone were compared with that of the PfCP-2.9.


RESULTS
Confident backbone assignments were obtained for 122 out of 241 residues of PfCP-2.9. The assigned residues in PfCP-2.9 were very similar to those previously reported for the individual domains. The conformation of the PfMSP1-19 in different constructs is essentially the same. Comparison of transverse relaxation rates (R2) strongly suggests no weak interaction between the domains.


CONCLUSIONS
These data indicate that the fusion of AMA-1(III) and MSP1-19 as chimeric protein did not change their structures, supporting the use of the chimeric protein as a potential malaria vaccine.
Department of Pathogenic Biology, State Key Laboratory of Medical Immunology, Second Military Medical University, Shanghai 200433, China.
Heng
H
Peng
Yunfei
Y
Hu
Aiguo
A
Zhou
Changwen
C
Jin
Weiqing
W
Pan
D000595:Amino Acid Sequence; D000818:Animals; D000953:Antigens, Protozoan / Q000737:chemistry*; D004797:Enzyme-Linked Immunosorbent Assay; D017780:Malaria Vaccines / Q000737:chemistry*; D008565:Membrane Proteins / Q000737:chemistry*; D020066:Merozoite Surface Protein 1 / Q000737:chemistry*; D008969:Molecular Sequence Data; D019906:Nuclear Magnetic Resonance, Biomolecular; D010843:Pichia; D010963:Plasmodium falciparum / Q000737:chemistry*; D011487:Protein Conformation; D015800:Protozoan Proteins / Q000737:chemistry*; D011993:Recombinant Fusion Proteins / Q000737:chemistry*; D014614:Vaccines, Synthetic / Q000737:chemistry
D000953:Antigens, Protozoan; D017780:Malaria Vaccines; D008565:Membrane Proteins; D020066:Merozoite Surface Protein 1; C535092:PfCP2.9 vaccine; D015800:Protozoan Proteins; D011993:Recombinant Fusion Proteins; D014614:Vaccines, Synthetic; C090077:apical membrane antigen I, Plasmodium