Mechanism of the phosphatase component of Clostridium thermocellum polynucleotide kinase-phosphatase
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چکیده
منابع مشابه
Characterization of the 2′,3′ cyclic phosphodiesterase activities of Clostridium thermocellum polynucleotide kinase-phosphatase and bacteriophage λ phosphatase
Clostridium thermocellum polynucleotide kinase-phosphatase (CthPnkp) catalyzes 5' and 3' end-healing reactions that prepare broken RNA termini for sealing by RNA ligase. The central phosphatase domain of CthPnkp belongs to the dinuclear metallophosphoesterase superfamily exemplified by bacteriophage lambda phosphatase (lambda-Pase). CthPnkp is a Ni(2+)/Mn(2+)-dependent phosphodiesterase-monoest...
متن کاملStructure-function analysis of the 3' phosphatase component of T4 polynucleotide kinase/phosphatase.
T4 polynucleotide kinase/phosphatase (Pnkp) exemplifies a family of bifunctional enzymes with 5'-kinase and 3' phosphatase activities that function in nucleic acid repair. T4 Pnkp is a homotetramer of a 301-aa polypeptide, which consists of an N-terminal kinase domain of the P-loop phosphotransferase superfamily and a C-terminal phosphatase domain of the DxD acylphosphatase superfamily. The hom...
متن کاملDistinct enzymic functional groups are required for the phosphomonoesterase and phosphodiesterase activities of Clostridium thermocellum polynucleotide kinase/phosphatase.
The central phosphatase domain of Clostridium thermocellum polynucleotide kinase/phosphatase (CthPnkp) belongs to the dinuclear metallophosphoesterase superfamily. Prior mutational studies of CthPnkp identified 7 individual active site side chains (Asp-187, His-189, Asp-233, Asn-263, His-323, His-376, and Asp-392) required for Ni2+-dependent hydrolysis of p-nitrophenyl phosphate. Here we find t...
متن کاملDNA end processing by polynucleotide kinase/phosphatase.
S cission of one or both strands of the DNA duplex occurs as ionizing radiation and oxidative DNA damage mount a constant assault our genomes. Like a broken limb, or split piece of wood, DNA strand breaks are typically not clean. That is, they lack the DNA 3′-hydroxyl and 5′-phosphate moieties needed for DNA repair synthesis by DNA polymerases and DNA end joining by DNA ligases (Fig. 1A). For i...
متن کاملRole of polynucleotide kinase/phosphatase in mitochondrial DNA repair
Mutations in mitochondrial DNA (mtDNA) are implicated in a broad range of human diseases and in aging. Compared to nuclear DNA, mtDNA is more highly exposed to oxidative damage due to its proximity to the respiratory chain and the lack of protection afforded by chromatin-associated proteins. While repair of oxidative damage to the bases in mtDNA through the base excision repair pathway has been...
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ژورنال
عنوان ژورنال: RNA
سال: 2006
ISSN: 1355-8382
DOI: 10.1261/rna.2196406