RESUMO
The gene coding for the key glycolytic enzyme fructose-1,6-diphosphate aldolase of the human malaria parasite Plasmodium falciparum lacks a functional AUG initiation codon for translation. Protein sequences of natural or in vitro translated aldolase include the candidate start methionine residue at internal positions. No additional AUG start codon is found in genomic DNA, cDNA or mRNA sequences. Instead, a UAG chain termination codon is recognized as the start signal of protein synthesis in vivo and in vitro.
Assuntos
Frutose-Bifosfato Aldolase/genética , Plasmodium falciparum/genética , Biossíntese de Proteínas/genética , Sequência de Aminoácidos , Animais , Sequência de Bases , Códon/genética , Dados de Sequência Molecular , Conformação de Ácido Nucleico , Plasmodium falciparum/enzimologia , RNA Mensageiro/genética , Reticulócitos/metabolismo , Regiões Terminadoras Genéticas/genéticaRESUMO
Immunization with a 41-kilodalton blood stage antigen (p41) of Plasmodium falciparum induces immunity to malaria in monkeys. However, antigenic polymorphism and repetitive amino acids commonly found in protective antigens complicate vaccine development. The gene encoding p41 has now been cloned and analyzed. Sequencing and hybridization studies revealed that the gene structure is highly conserved in 14 parasite isolates from three continents. This finding and the lack of repetitive amino acids in the translated DNA sequence may indicate that p41 has an essential function. In this study the protein was found to be 60 percent homologous to the key glycolytic enzyme aldolase from vertebrates, and the affinity-purified p41 protein from parasites showed aldolase activity.
