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PMID:15968050
| Citation |
Merdanovic, M, Sauer, E and Reidl, J (2005) Coupling of NAD+ biosynthesis and nicotinamide ribosyl transport: characterization of NadR ribonucleotide kinase mutants of Haemophilus influenzae. J. Bacteriol. 187:4410-20 |
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| Abstract |
Previously, we characterized a pathway necessary for the processing of NAD+ and for uptake of nicotinamide riboside (NR) in Haemophilus influenzae. Here we report on the role of NadR, which is essential for NAD+ utilization in this organism. Different NadR variants with a deleted ribonucleotide kinase domain or with a single amino acid change were characterized in vitro and in vivo with respect to cell viability, ribonucleotide kinase activity, and NR transport. The ribonucleotide kinase mutants were viable only in a nadV+ (nicotinamide phosphoribosyltransferase) background, indicating that the ribonucleotide kinase domain is essential for cell viability in H. influenzae. Mutations located in the Walker A and B motifs and the LID region resulted in deficiencies in both NR phosphorylation and NR uptake. The ribonucleotide kinase function of NadR was found to be feedback controlled by NAD+ under in vitro conditions and by NAD+ utilization in vivo. Taken together, our data demonstrate that the NR phosphorylation step is essential for both NR uptake across the inner membrane and NAD+ synthesis and is also involved in controlling the NAD+ biosynthesis rate. |
| Links |
PubMed PMC1151767 Online version:10.1128/JB.187.13.4410-4420.2005 |
| Keywords |
Amino Acid Motifs; Bacterial Proteins/metabolism; Catalytic Domain; Cell Membrane/metabolism; Haemophilus influenzae/enzymology; Haemophilus influenzae/genetics; Mutation; NAD/biosynthesis; Niacinamide/analogs & derivatives; Niacinamide/metabolism; Nicotinamide Phosphoribosyltransferase; Pentosyltransferases/physiology; Phosphorylation; Phosphotransferases/genetics; Protein Transport; Repressor Proteins/metabolism; Ribonucleotides |
| edit table |
Significance
Annotations
| Gene product | Qualifier | GO Term | Evidence Code | with/from | Aspect | Extension | Notes | Status |
|---|---|---|---|---|---|---|---|---|
| GO:0000309: nicotinamide-nucleotide adenylyltransferase activity |
ECO:0000315: |
F |
In Figure 1, lanes 3 and 4, have had the RNK domain of NadR deleted. These lanes show no in vivo NAD+ synthesis. |
complete | ||||
See also
References
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