3n9b
Crystal Structure of the P. aeruginosa LigD phosphoesterase domain
Structural highlights
FunctionLIGD_PSEAE With Ku probably forms a non-homologous end joining (NHEJ) repair enzyme, which repairs dsDNA breaks (DSB) with reduced fidelity. Acts as a DNA ligase on singly nicked dsDNA, fills dsDNA gaps (3- or 4- nucleotide gaps, prefers a 5'-phosphate at the gap distal end, prefers dNTPs over rNTPs) (PubMed:20018881), has DNA-directed DNA polymerase activity (templated primer extension) and DNA-directed RNA polymerase activity (PubMed:15897197), adds 1 or 2 non-templated rNTP (or less well dNTP) to ssDNA or blunt-end dsDNA (primer extension). Has 3' resection activity, removing 3'-rNMPs from DNA using its 3'-ribonuclease and 3'-phosphatase activities sequentially. Resection requires a 2'-OH in the penultimate nucleoside position (i.e. a ribo- not deoxyribonucleoside) (PubMed:15897197), although the 3'-phosphatase activity does not, and its specific activity is 16-fold higher on a DNA substrate (PubMed:16046407). On appropriate substrates will extend a DNA primer to the end of the template strand and then incorporate a non-templated nucleotide.[1] [2] [3] The preference of the polymerase domain for rNTPs over dNTPs may be advantageous in quiescent cells where the dNTP pool may be limiting. 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 PubMedThe DNA ligase D (LigD) 3'-phosphoesterase (PE) module is a conserved component of the bacterial nonhomologous end-joining (NHEJ) apparatus that performs 3' end-healing reactions at DNA double-strand breaks. Here we report the 1.9 A crystal structure of Pseudomonas aeruginosa PE, which reveals that PE exemplifies a unique class of DNA repair enzyme. PE has a distinctive fold in which an eight stranded beta barrel with a hydrophobic interior supports a crescent-shaped hydrophilic active site on its outer surface. Six essential side chains coordinate manganese and a sulfate mimetic of the scissile phosphate. The PE active site and mechanism are unique vis a vis other end-healing enzymes. We find PE homologs in archaeal and eukaryal proteomes, signifying that PEs comprise a DNA repair superfamily. Structure of bacterial LigD 3'-phosphoesterase unveils a DNA repair superfamily.,Nair PA, Smith P, Shuman S Proc Natl Acad Sci U S A. 2010 Jul 20;107(29):12822-7. Epub 2010 Jun 29. PMID:20616014[4] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. References
| ||||||||||||||||||||
