4dy9
Leishmania major Peroxidase is a Cytochrome c Peroxidase
Structural highlights
FunctionQ4QEN5_LEIMA Electron carrier protein. The oxidized form of the cytochrome c heme group can accept an electron from the heme group of the cytochrome c1 subunit of cytochrome reductase. Cytochrome c then transfers this electron to the cytochrome oxidase complex, the final protein carrier in the mitochondrial electron-transport chain.[RuleBase:RU004427] Publication Abstract from PubMedLeishmania major peroxidase (LmP) exhibits both ascorbate and cytochrome c peroxidase activity. Our previous results illustrated that LmP has much higher activity against horse heart cytochrome c than ascorbate suggesting that cytochrome c may be the biologically important substrate. In order to elucidate the biological function of LmP, we have recombinantly expressed, purified and determined the 2.08A crystal structure of Leishmania major cytochrome c (LmCytc). Like other cytochromes c LmCytc has an electropositive surface surrounding the exposed heme edge that serves as the docking site with redox partners. LmCytc exhibits a unique UV-Visible reduced spectrum from most cytochromes because it has only one cysteine and therefore only one heme vinyl-thioether bond. Kinetic assays performed with LmCytc and LmP show that LmCytc is a much better substrate for LmP than horse heart cytochrome c. Furthermore, unlike the well-studied yeast system, the reaction follows classic Michaelis-Menten kinetics and is sensitive to increasing ionic strength. Using the yeast co-crystal as a control, protein-protein docking was performed using Rosetta to develop a model for the binding of LmP and LmCytc. These results suggest that the biological function of LmP is to act as a cytochrome c peroxidase. LEISHMANIA MAJOR PEROXIDASE IS A CYTOCHROME C PEROXIDASE.,Jasion VS, Poulos TL Biochemistry. 2012 Feb 29. PMID:22372542[1] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. See AlsoReferences
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