1lw7
NADR PROTEIN FROM HAEMOPHILUS INFLUENZAE
Structural highlights
FunctionNADR_HAEIN This enzyme has two activities: nicotinamide mononucleotide (NMN) adenylyltransferase and ribosylnicotinamide (RN) kinase. The RN kinase activity catalyzes the phosphorylation of RN to form nicotinamide ribonucleotide. The NMN adenylyltransferase activity catalyzes the transfer of the AMP moiety of ATP to nicotinamide ribonucleotide to form NAD(+).[1] 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 PubMedHaemophilus influenzae NadR protein (hiNadR) has been shown to be a bifunctional enzyme possessing both NMN adenylytransferase (NMNAT; EC ) and ribosylnicotinamide kinase (RNK; EC ) activities. Its function is essential for the growth and survival of H. influenzae and thus may present a new highly specific anti-infectious drug target. We have solved the crystal structure of hiNadR complexed with NAD using the selenomethionine MAD phasing method. The structure reveals the presence of two distinct domains. The N-terminal domain that hosts the NMNAT activity is closely related to archaeal NMNAT, whereas the C-terminal domain, which has been experimentally demonstrated to possess ribosylnicotinamide kinase activity, is structurally similar to yeast thymidylate kinase and several other P-loop-containing kinases. There appears to be no cross-talk between the two active sites. The bound NAD at the active site of the NMNAT domain reveals several critical interactions between NAD and the protein. There is also a second non-active-site NAD molecule associated with the C-terminal RNK domain that adopts a highly folded conformation with the nicotinamide ring stacking over the adenine base. Whereas the RNK domain of the hiNadR structure presented here is the first structural characterization of a ribosylnicotinamide kinase from any organism, the NMNAT domain of hiNadR defines yet another member of the pyridine nucleotide adenylyltransferase family. Crystal structure of Haemophilus influenzae NadR protein. A bifunctional enzyme endowed with NMN adenyltransferase and ribosylnicotinimide kinase activities.,Singh SK, Kurnasov OV, Chen B, Robinson H, Grishin NV, Osterman AL, Zhang H J Biol Chem. 2002 Sep 6;277(36):33291-9. Epub 2002 Jun 14. PMID:12068016[2] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. References
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