Publication Date:
2012-03-14
Description:
The phosphoesterase (PE) domain of the bacterial DNA repair enzyme LigD possesses distinctive manganese-dependent 3'-phosphomonoesterase and 3'-phosphodiesterase activities. PE exemplifies a new family of DNA end-healing enzymes found in all phylogenetic domains. Here, we determined the structure of the PE domain of Pseudomonas aeruginosa LigD ( Pae PE) using solution NMR methodology. Pae PE has a disordered N-terminus and a well-folded core that differs in instructive ways from the crystal structure of a Pae PE•Mn 2+ • sulfate complex, especially at the active site that is found to be conformationally dynamic. Chemical shift perturbations in the presence of primer-template duplexes with 3'-deoxynucleotide, 3'-deoxynucleotide 3'-phosphate, or 3' ribonucleotide termini reveal the surface used by Pae PE to bind substrate DNA and suggest a more efficient engagement in the presence of a 3'-ribonucleotide. Spectral perturbations measured in the presence of weakly catalytic (Cd 2+ ) and inhibitory (Zn 2+ ) metals provide evidence for significant conformational changes at and near the active site, compared to the relatively modest changes elicited by Mn 2+ .
Print ISSN:
0305-1048
Electronic ISSN:
1362-4962
Topics:
Biology
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