Amino acid sequence of the serine-repeat antigen (SERA) of Plasmodium falciparum determined from cloned cDNA.
We report the isolation of cDNA clones for a Plasmodium falciparum gene that encodes the complete amino acid sequence of a previously identified exported blood stage antigen. The Mr of this antigen protein had been determined by sodium dodecylsulphate-polyacrylamide gel electrophoresis analysis, by different workers, to be 113,000, 126,000, and 140,000. We show, by cDNA nucleotide sequence analysis, that this antigen gene encodes a 989 amino acid protein (111 kDa) that contains a potential signal peptide, but not a membrane anchor domain. In the FCR3 strain the serine content of the protein was 11%, of which 57% of the serine residues were localized within a 201 amino acid sequence that included 35 consecutive serine residues. The protein also contained three possible N-linked glycosylation sites and numerous possible O-linked glycosylation sites. The mRNA was abundant during late trophozoite-schizont parasite stages. We propose to identity this antigen, which had been called p126, by the acronym SERA, serine-repeat antigen, based on its complete structure. The usefulness of the cloned cDNA as a source of a possible malaria vaccine is considered in view of the previously demonstrated ability of the antigen to induce parasite-inhibitory antibodies and a protective immune response in Saimiri monkeys.
Bzik
D J
DJ
Department of Microbiology, Dartmouth Medical School, Hanover, NH 03756.
Li
W B
WB
Horii
T
T
Inselburg
J
J
D000595:Amino Acid Sequence; D000818:Animals; D000953:Antigens, Protozoan / Q000096:biosynthesis / Q000276:immunology; D001483:Base Sequence; D015152:Blotting, Northern; D015139:Blotting, Southern; D003001:Cloning, Molecular; D004247:DNA / Q000235:genetics; D004720:Endonucleases; D008969:Molecular Sequence Data; D010957:Plasmids; D010963:Plasmodium falciparum / Q000235:genetics*; D015183:Restriction Mapping; D015719:Single-Strand Specific DNA and RNA Endonucleases
D000953:Antigens, Protozoan; C057495:serine repeat antigen, Plasmodium; D004247:DNA; D004720:Endonucleases; D015719:Single-Strand Specific DNA and RNA Endonucleases