title: Localization of pyruvate:NADP+ oxidoreductase in sporozoites of Cryptosporidium parvum.
abstract: Cryptosporidium parvum contains a unique fusion protein pyruvate:NADP+ oxidoreductase (CpPNO) that is composed of two distinct, conserved domains, an N-terminal pyruvate:ferredoxin oxidoreductase (PFO) and a C-terminal cytochrome P450 reductase (CPR). Unlike a similar fusion protein that localizes to the mitochondrion of the photosynthetic protist Euglena gracilis, CpPNO lacks an N-terminal mitochondrial targeting sequence. Using two distinct polyclonal antibodies raised against CpPFO and one polyclonal antibody against CpCPR, Western blot analysis has shown that sporozoites of C. parvum express the entire CpPNO fusion protein. Furthermore, confocal immunofluorescence and transmission electron microscopy confirm that CpPNO is localized within the cytosol rather than the relict mitochondrion of C. parvum. The distribution of this protein is not, however, strictly confined to the cytosol. CpPNO also appears to localize posteriorly within the crystalloid body.
authors.affiliation: Department of Tropical Medicine, 1st Faculty of Medicine, Charles University, Prague, Czech Republic. vlastaxiv@hotmail.com
authors.forename: Vlasta
authors.initials: V
authors.lastname: Ctrnacta
authors.forename: Jeffrey G
authors.initials: JG
authors.lastname: Ault
authors.forename: Frantisek
authors.initials: F
authors.lastname: Stejskal
authors.forename: Janet S
authors.initials: JS
authors.lastname: Keithly
mesh_terms: D000818:Animals; D015153:Blotting, Western; D016785:Cryptosporidium parvum / Q000166:cytology / Q000201:enzymology* / Q000235:genetics / Q000254:growth & development; D003600:Cytosol / Q000201:enzymology; D005056:Euglena gracilis / Q000166:cytology / Q000201:enzymology; D007658:Ketone Oxidoreductases / Q000032:analysis* / Q000235:genetics / Q000276:immunology; D018613:Microscopy, Confocal; D046529:Microscopy, Electron, Transmission; D008856:Microscopy, Fluorescence; D009251:NADPH-Ferrihemoprotein Reductase / Q000032:analysis* / Q000235:genetics / Q000276:immunology; D015388:Organelles / Q000201:enzymology; D015800:Protozoan Proteins / Q000032:analysis; D050743:Pyruvate Synthase / Q000032:analysis* / Q000235:genetics / Q000276:immunology; D034101:Sporozoites / Q000166:cytology / Q000201:enzymology* / Q000235:genetics
chemical_list: D015800:Protozoan Proteins; D007658:Ketone Oxidoreductases; C053164:pyruvate dehydrogenase (NADP+); D050743:Pyruvate Synthase; D009251:NADPH-Ferrihemoprotein Reductase