Structural highlights
Function
[KIPN_BPT4] Acts as a 5'-hydroxyl kinase, a 3'-phosphatase and a 2',3'-cyclic phosphodiesterase. Catalyzes the transfer of the terminal phosphate of ATP to the 5'-hydroxyl termini of ribo- and deoxyribonucleotides. In the presence of ADP the enzyme also catalyzes an exchange reaction. In the exchange reaction, an excess ADP causes the enzyme to transfer the 5' terminal phosphate from phosphorylated DNA to ADP. These activities modify the ends of nicked tRNA generated by a bacterial response to infection and facilitate repair by T4 RNA ligase.
Evolutionary Conservation
Check, as determined by ConSurfDB. You may read the explanation of the method and the full data available from ConSurf.
Publication Abstract from PubMed
T4 phage polynucleotide kinase (PNK) displays 5'-hydroxyl kinase, 3'-phosphatase and 2',3'-cyclic phosphodiesterase activities. The enzyme phosphorylates the 5' hydroxyl termini of a wide variety of nucleic acid substrates, a behavior studied here through the determination of a series of crystal structures with single-stranded (ss)DNA oligonucleotide substrates of various lengths and sequences. In these structures, the 5' ribose hydroxyl is buried in the kinase active site in proper alignment for phosphoryl transfer. Depending on the ssDNA length, the first two or three nucleotide bases are well ordered. Numerous contacts are made both to the phosphoribosyl backbone and to the ordered bases. The position, side chain contacts and internucleotide stacking interactions of the ordered bases are strikingly different for a 5'-GT DNA end than for a 5'-TG end. The base preferences displayed at those positions by PNK are attributable to differences in the enzyme binding interactions and in the DNA conformation for each unique substrate molecule.
Recognition of DNA substrates by T4 bacteriophage polynucleotide kinase.,Eastberg JH, Pelletier J, Stoddard BL Nucleic Acids Res. 2004 Jan 30;32(2):653-60. Print 2004. PMID:14754987[1]
From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.
References
- ↑ Eastberg JH, Pelletier J, Stoddard BL. Recognition of DNA substrates by T4 bacteriophage polynucleotide kinase. Nucleic Acids Res. 2004 Jan 30;32(2):653-60. Print 2004. PMID:14754987 doi:10.1093/nar/gkh212
