Structural rearrangement accompanying NAD+ synthesis within a bacterial DNA ligase crystal.
DNA ligase is an enzyme important for DNA repair and replication. Eukaryotic genomes encode ligases requiring ATP as the cofactor; bacterial genomes encode NAD(+)-dependent ligase. This difference in substrate specificities and the essentiality of NAD(+)-dependent ligase for bacterial survival make NAD(+)-dependent ligase a good target for designing highly specific anti-infectives. Any such structure-guided effort would require the knowledge of the precise mechanism of NAD+ recognition by the enzyme. We report the principles of NAD+ recognition by presenting the synthesis of NAD+ from nicotinamide mononucleotide (NMN) and AMP, catalyzed by Enterococcus faecalis ligase within the crystal lattice. Unprecedented conformational change, required to reorient the two subdomains of the protein for the condensation to occur and to recognize NAD+, is captured in two structures obtained using the same protein crystal. Structural data and sequence analysis presented here confirms and extends prior functional studies of the ligase adenylation reaction.
Quorex Pharmaceuticals, 1890 Rutherford Road, Suite 200, Carlsbad, California 92008, USA. ketang@quorex.com
Ketan S
KS
Gajiwala
Christopher
C
Pinko
D003001:Cloning, Molecular; D003460:Crystallization; D018360:Crystallography, X-Ray; D011088:DNA Ligases / Q000737:chemistry*; D013293:Enterococcus faecalis / Q000201:enzymology; D008958:Models, Molecular; D009243:NAD / Q000737:chemistry*; D009537:Nicotinamide Mononucleotide / Q000737:chemistry*; D017434:Protein Structure, Tertiary
D009243:NAD; D009537:Nicotinamide Mononucleotide; D011088:DNA Ligases; C120640:DNA ligase (NAD)