2I2B: Crystal structure of LmNADK1 from Listeria monocytogenes

Here we describe the crystal structures of the NAD kinase (LmNADK1) from Listeria monocytogenes in complex with its substrate NAD, its product NADP, or two synthesized NAD mimics. We identified one of the NAD mimics, di-adenosine diphosphate, as a new substrate for LmNADK1, whereas we showed that the closely related compound di-5'-thioadenosine is a novel non-natural inhibitor for this enzyme. These structures suggest a mechanism involving substrate-assisted catalysis. Indeed, sequence/structure comparison and directed mutagenesis have previously shown that NAD kinases (NADKs) and the distantly related 6-phosphofructokinases share the same catalytically important GGDGT motif. However, in this study we have shown that these enzymes use the central aspartate of this motif differently. Although this acidic residue chelates the catalytic Mg(2+) ion in 6-phosphofructokinases, it activates the phospho-acceptor (NAD) in NADKs. Sequence/structure comparisons suggest that the role of this aspartate would be conserved in NADKs and the related sphingosine and diacylglycerol kinases.
PDB ID: 2I2BDownload
MMDB ID: 53460
PDB Deposition Date: 2006/8/16
Updated in MMDB: 2008/11
Experimental Method:
x-ray diffraction
Resolution: 2.1  Å
Source Organism:
Similar Structures:
Biological Unit for 2I2B: tetrameric; determined by author
Molecular Components in 2I2B
Label Count Molecule
Proteins (4 molecules)
Probable Inorganic Polyphosphate/atp-nad Kinase 1(Gene symbol: ppnK)
Molecule annotation
Chemicals (16 molecules)
* Click molecule labels to explore molecular sequence information.

Citing MMDB