Two Plasmodium falciparum ribonucleotide reductase small subunits, PfR2 and PfR4, interact with each other and are components of the in vivo enzyme complex
Abbreviated Journal Title
J. Mol. Biol.
malaria; Plasmodium falciparum; ribonucleotide reductase; deoxyribonucletide; CELL-CYCLE; DNA-DAMAGE; PROTEIN; YEAST; LOCALIZATION; EXPRESSION; MALARIA; IDENTIFICATION; PURIFICATION; CHECKPOINT; Biochemistry & Molecular Biology
Ribonucleotide reductase (RNR) is a tetrameric enzyme, composed of two large (R1) and two small (R2) subunits, which regulates the nucleotide balance in cells by controlling the rate-limiting step for deoxyribonucleotide synthesis. We have identified a second copy of the small subunit gene, termed PfR4, encoding a 324 amino acid residue polypeptide that shares only 25% identity with the previously identified PfR2 small subunit of Plasmodium falciparum. PfR4 expression is cell-cycle-regulated, and the profile of transcript and protein expression corresponds to that of PfR2. A 1.3 kb PfR4 5 '-flanking fragment contained a functional promoter activity. We have detected interaction between PfR2 and PfR4 by co-immunoprecipitation experiments. Indirect immunofluorescence analysis showed distinct localization of two small RNR subunits with some colocalization. The association of PfR1 large subunit with PfR4 was detected by GST pull-down assay. This interaction is reduced significantly when using a PfR4 truncated at the COOH terminus, suggesting the involvement of COOH-terminal residues in PfR4-PfR1 interaction. All three RNR subunits co-eluted on a Superose 12 size-exclusion column corresponding to fractions with a molecular mass of around 250 kDa. This suggests the existence of all three RNR subunits in Plasmodium in a native complex of alpha(2)beta beta ' configuration. (c) 2005 Elsevier Ltd. All rights reserved.
Journal of Molecular Biology
"Two Plasmodium falciparum ribonucleotide reductase small subunits, PfR2 and PfR4, interact with each other and are components of the in vivo enzyme complex" (2005). Faculty Bibliography 2000s. 5004.