Functional Characterization of a Novel Thioredoxin Domain-Containing Protein of the Malaria Parasite Plasmodium

摘要: A novel thioredoxin domain-containing protein of the malaria parasite Plasmodium was identified and found to be conserved among eukaryotes. This protein belongs phosducin-like family proteins (PhLPs), was therefore assigned name PhLP1, since it is first phosducin-like identified in Plasmodium. PhLPs have been have various roles G-protein signaling, cell cycle progression, folding. However, biochemical mechanism by which perform their function unknown. Here is described cloning biochemical characterization both PhLP1 its human homolog TXNDC9. Both purified PhLP1 TXNDC9 showed enzymatic activity insulin reduction assay were also active thioredoxin-couple assay. Sequence alignment homologous modeling TXNDC9 indicated a conserved, putative atypical site place typical catalytic CXXC motif classical redox thioredoxins. Site-directed mutagenesis cysteine (C106) abolished functions protein, confirming role C106 catalytic mechanisms the protein. These results show for first time that are redox active enzymes can efficiently reduced thioredoxin system. findings shed new light on mechanism and biological these highly conserved proteins.