The Experts below are selected from a list of 9 Experts worldwide ranked by ideXlab platform
Xiuguo Zhang - One of the best experts on this subject based on the ideXlab platform.
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Structural and catalytic analysis of two diverse uridine phosphorylases in Phytophthora capsici.
Scientific reports, 2020Co-Authors: Cancan Yang, Li Jing, Zhenling Huang, Xuefa Zhang, Xiaolei Gao, Chunyuang Zhu, Paul F. Morris, Xiuguo ZhangAbstract:Uridine phosphorylase (UP) is a key enzyme of pyrimidine salvage pathways that enables the recycling of endogenous or exogenous-supplied pyrimidines and plays an important intracellular metabolic role. Here, we biochemically and structurally characterized two evolutionarily divergent uridine phosphorylases, PcUP1 and PcUP2 from the oomycete pathogen Phytophthora capsici. Our analysis of other oomycete genomes revealed that both uridine phosphorylases are present in Phytophthora and Pythium genomes, but only UP2 is seen in Saprolegnia spp. which are basal members of the oomycetes. Moreover, uridine phosphorylases are not found in obligate oomycete pathogens such as Hyaloperonospora arabidopsidis and Albugo spp. PcUP1 and PcUP2 are upregulated 300 and 500 fold respectively, within 90 min after infection of pepper leaves. The crystal structures of PcUP1 in ligand-free and in complex with uracil/ribose-1-Phosphate, 2'-Deoxyuridine/Phosphate and thymidine/Phosphate were analyzed. Crystal structure of this uridine phosphorylase showed strict conservation of key residues in the binding pocket. Structure analysis of PcUP1 with bound ligands, and site-directed mutagenesis of key residues provide additional support for the "push-pull" model of catalysis. Our study highlights the importance of pyrimidine salvage during the earliest stages of infection.
Cancan Yang - One of the best experts on this subject based on the ideXlab platform.
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Structural and catalytic analysis of two diverse uridine phosphorylases in Phytophthora capsici.
Scientific reports, 2020Co-Authors: Cancan Yang, Li Jing, Zhenling Huang, Xuefa Zhang, Xiaolei Gao, Chunyuang Zhu, Paul F. Morris, Xiuguo ZhangAbstract:Uridine phosphorylase (UP) is a key enzyme of pyrimidine salvage pathways that enables the recycling of endogenous or exogenous-supplied pyrimidines and plays an important intracellular metabolic role. Here, we biochemically and structurally characterized two evolutionarily divergent uridine phosphorylases, PcUP1 and PcUP2 from the oomycete pathogen Phytophthora capsici. Our analysis of other oomycete genomes revealed that both uridine phosphorylases are present in Phytophthora and Pythium genomes, but only UP2 is seen in Saprolegnia spp. which are basal members of the oomycetes. Moreover, uridine phosphorylases are not found in obligate oomycete pathogens such as Hyaloperonospora arabidopsidis and Albugo spp. PcUP1 and PcUP2 are upregulated 300 and 500 fold respectively, within 90 min after infection of pepper leaves. The crystal structures of PcUP1 in ligand-free and in complex with uracil/ribose-1-Phosphate, 2'-Deoxyuridine/Phosphate and thymidine/Phosphate were analyzed. Crystal structure of this uridine phosphorylase showed strict conservation of key residues in the binding pocket. Structure analysis of PcUP1 with bound ligands, and site-directed mutagenesis of key residues provide additional support for the "push-pull" model of catalysis. Our study highlights the importance of pyrimidine salvage during the earliest stages of infection.
John F. Cutfield - One of the best experts on this subject based on the ideXlab platform.
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Crystal structures of escherichia coli uridine phosphorylase in two native and three complexed forms reveal basis of substrate specificity, induced conformational changes and influence of potassium
Journal of molecular biology, 2004Co-Authors: Tom T. Caradoc-davies, S.m. Cutfield, Iain L. Lamont, John F. CutfieldAbstract:Uridine phosphorylase (UP) is a key enzyme in the pyrimidine salvage pathway that catalyses the reversible phosphorolysis of uridine to uracil and ribose 1-Phosphate. Inhibiting liver UP in humans raises blood uridine levels and produces a protective effect ("uridine rescue") against the toxicity of the chemotherapeutic agent 5-fluorouracil without reducing its antitumour activity. We have investigated UP-substrate interactions by determining the crystal structures of native Escherichia coli UP (two forms), and complexes with 5-fluorouracil/ribose 1-Phosphate, 2-Deoxyuridine/Phosphate and thymidine/Phosphate. These hexameric structures confirm the overall structural similarity of UP to E.coli purine nucleoside phosphorylase (PNP) whereby, in the presence of substrate, each displays a closed conformation resulting from a concerted movement that closes the active site cleft. However, in contrast to PNP where helix segmentation is the major conformational change between the open and closed forms, in UP more extensive changes are observed. In particular a swinging movement of a flap region consisting of residues 224-234 seals the active site. This overall change in conformation results in compression of the active site cleft. Gln166 and Arg168, part of an inserted segment not seen in PNP, are key residues in the uracil binding pocket and together with a tightly bound water molecule are seen to be involved in the substrate specificity of UP. Enzyme activity shows a twofold dependence on potassium ion concentration. The presence of a potassium ion at the monomer/monomer interface induces some local rearrangement, which results in dimer stabilisation. The conservation of key residues and interactions with substrate in the Phosphate and ribose binding pockets suggest that ribooxocarbenium ion formation during catalysis of UP may be similar to that proposed for E.coli PNP.
Zhenling Huang - One of the best experts on this subject based on the ideXlab platform.
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Structural and catalytic analysis of two diverse uridine phosphorylases in Phytophthora capsici.
Scientific reports, 2020Co-Authors: Cancan Yang, Li Jing, Zhenling Huang, Xuefa Zhang, Xiaolei Gao, Chunyuang Zhu, Paul F. Morris, Xiuguo ZhangAbstract:Uridine phosphorylase (UP) is a key enzyme of pyrimidine salvage pathways that enables the recycling of endogenous or exogenous-supplied pyrimidines and plays an important intracellular metabolic role. Here, we biochemically and structurally characterized two evolutionarily divergent uridine phosphorylases, PcUP1 and PcUP2 from the oomycete pathogen Phytophthora capsici. Our analysis of other oomycete genomes revealed that both uridine phosphorylases are present in Phytophthora and Pythium genomes, but only UP2 is seen in Saprolegnia spp. which are basal members of the oomycetes. Moreover, uridine phosphorylases are not found in obligate oomycete pathogens such as Hyaloperonospora arabidopsidis and Albugo spp. PcUP1 and PcUP2 are upregulated 300 and 500 fold respectively, within 90 min after infection of pepper leaves. The crystal structures of PcUP1 in ligand-free and in complex with uracil/ribose-1-Phosphate, 2'-Deoxyuridine/Phosphate and thymidine/Phosphate were analyzed. Crystal structure of this uridine phosphorylase showed strict conservation of key residues in the binding pocket. Structure analysis of PcUP1 with bound ligands, and site-directed mutagenesis of key residues provide additional support for the "push-pull" model of catalysis. Our study highlights the importance of pyrimidine salvage during the earliest stages of infection.
Xuefa Zhang - One of the best experts on this subject based on the ideXlab platform.
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Structural and catalytic analysis of two diverse uridine phosphorylases in Phytophthora capsici.
Scientific reports, 2020Co-Authors: Cancan Yang, Li Jing, Zhenling Huang, Xuefa Zhang, Xiaolei Gao, Chunyuang Zhu, Paul F. Morris, Xiuguo ZhangAbstract:Uridine phosphorylase (UP) is a key enzyme of pyrimidine salvage pathways that enables the recycling of endogenous or exogenous-supplied pyrimidines and plays an important intracellular metabolic role. Here, we biochemically and structurally characterized two evolutionarily divergent uridine phosphorylases, PcUP1 and PcUP2 from the oomycete pathogen Phytophthora capsici. Our analysis of other oomycete genomes revealed that both uridine phosphorylases are present in Phytophthora and Pythium genomes, but only UP2 is seen in Saprolegnia spp. which are basal members of the oomycetes. Moreover, uridine phosphorylases are not found in obligate oomycete pathogens such as Hyaloperonospora arabidopsidis and Albugo spp. PcUP1 and PcUP2 are upregulated 300 and 500 fold respectively, within 90 min after infection of pepper leaves. The crystal structures of PcUP1 in ligand-free and in complex with uracil/ribose-1-Phosphate, 2'-Deoxyuridine/Phosphate and thymidine/Phosphate were analyzed. Crystal structure of this uridine phosphorylase showed strict conservation of key residues in the binding pocket. Structure analysis of PcUP1 with bound ligands, and site-directed mutagenesis of key residues provide additional support for the "push-pull" model of catalysis. Our study highlights the importance of pyrimidine salvage during the earliest stages of infection.