Cloning of a pyruvate phosphate dikinase from Trypanosoma cruzi.
We have cloned and characterised a gene that encodes a putative pyruvate phosphate dikinase (PPDK) from Trypanosoma cruzi, an enzyme that catalyses the reversible conversion of phosphoenolpyruvate to pyruvate. PPDK is absent in mammalian cells, but has been found in a wide variety of other organisms, including plants and bacteria. In T. cruzi, two genes (PPDK1 and PPDK2) are present in a tandem array localised on a 1 Mbp chromosome. Northern and Western blot analyses indicates that PPDK is expressed as a 100-kDa protein in epimastigote, amastigote and trypomastigote forms. PPDK1 and PPDK2 encode an identical protein of 100.8 kDa with a C-terminal extension ending with the sequence AKL, a signal for glycosomal import. Both T. cruzi and T. brucei enzymes possess a 23-residue insertion, that is absent in other PPDKs. A three-dimensional alignment with the crystal structure of the enzyme from Clostridium symbiosum predicts that this insertion is located on the surface of the nucleotide-binding domain. Phylogenetic studies indicate that bacterial and protist PPDKs cluster as a separate group from those of plants. The evolutionary implications and possible role of this enzyme in T. cruzi is discussed.
Division of Biological Chemistry and Molecular Microbiology, School of Life Sciences, Wellcome Trust Biocentre, University of Dundee, Dundee DD1 5EH, UK.
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Maldonado
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Fairlamb
D000595:Amino Acid Sequence; D000818:Animals; D015152:Blotting, Northern; D015139:Blotting, Southern; D015153:Blotting, Western; D020134:Catalytic Domain; D003001:Cloning, Molecular; D018507:Gene Expression Regulation, Developmental; D008958:Models, Molecular; D008969:Molecular Sequence Data; D010802:Phylogeny; D017434:Protein Structure, Tertiary; D011772:Pyruvate, Orthophosphate Dikinase / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D016415:Sequence Alignment; D014349:Trypanosoma cruzi / Q000201:enzymology* / Q000235:genetics* / Q000254:growth & development
D012333:RNA, Messenger; D011772:Pyruvate, Orthophosphate Dikinase