Cloning metabolic pathway genes by complementation in Escherichia coli. Isolation and expression of Plasmodium falciparum glucose phosphate isomerase

Genetic complementation of an Escherichia coli double mutant was used to isolate and express the gene coding for Plasmodium falciparum glucose phosphate isomerase. The gene contains a 1773-base pair open reading frame, has no introns, and maps to P. falciparum chromosome 14. 34% of the deduced amino acid sequence is identical to human glucose phosphate isomerase, with highest similarity in regions of the proposed active sites. The putative initiation site of translation was determined by deletional and oligonucleotide mediated, site-specific mutageneses. Our data suggest that key metabolic enzymes of Plasmodia can be cloned and expressed in E. coli without prior knowledge of the primary amino acid or nucleic acid structure.