Independent locations of kinase and 3'-phosphatase activities on T4 polynucleotide kinase.
نویسندگان
چکیده
منابع مشابه
Mutational analysis defines the 5'-kinase and 3'-phosphatase active sites of T4 polynucleotide kinase.
T4 polynucleotide kinase (Pnk) is a bifunctional 5'-kinase/3'-phosphatase that aids in the repair of broken termini in RNA by converting 3'-PO4/5'-OH ends into 3'-OH/5'-PO4 ends, which are then sealed by RNA ligase. Here we have employed site-directed mutagenesis (introducing 31 mutations at 16 positions) to locate candidate catalytic residues within the 301 amino acid Pnk polypeptide. We found...
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 کاملMechanism of RNA 2′,3′-cyclic phosphate end healing by T4 polynucleotide kinase–phosphatase
T4 polynucleotide kinase-phosphatase (Pnkp) exemplifies a family of enzymes with 5'-kinase and 3'-phosphatase activities that function in nucleic acid repair. The polynucleotide 3'-phosphatase reaction is executed by the Pnkp C-terminal domain, which belongs to the DxDxT acylphosphatase superfamily. The 3'-phosphatase reaction entails formation and hydrolysis of a covalent enzyme-(Asp165)-phosp...
متن کاملPolynucleotide kinase from a T4 mutant which lacks the 3' phosphatase activity.
Polynucleotide kinase from E. coli infected with the PseT 1 mutant of bacteriophage T4 has been isolated. The PseT 1 enzyme purifies similarly to normal polynucleotide kinase and effectively transfers the gamma phosphate of ATP to the 5' terminal hydroxyl of DNA and RNA. The PseT 1 and normal enzymes require similar magnesium ion concentrations, have the same pH optima and are both inhibited by...
متن کاملCharacterization 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...
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ژورنال
عنوان ژورنال: Journal of Biological Chemistry
سال: 1982
ISSN: 0021-9258
DOI: 10.1016/s0021-9258(18)33763-3