CATH Classification

Domain Context

CATH Clusters

Superfamily 3.40.1190.20
Functional Family

Enzyme Information

5.1.99.6
NAD(P)H-hydrate epimerase.
based on mapping to UniProt Q9X024
(1) (6R)-6-beta-hydroxy-1,4,5,6-tetrahydronicotinamide-adenine dinucleotide = (6S)-6-beta-hydroxy-1,4,5,6-tetrahydronicotinamide-adenine dinucleotide. (2) (6R)-6-beta-hydroxy-1,4,5,6-tetrahydronicotinamide-adenine dinucleotide phosphate = (6S)-6-beta-hydroxy-1,4,5,6- tetrahydronicotinamide-adenine dinucleotide phosphate.
-!- The enzyme can use either (R)-NADH-hydrate or (R)-NADPH-hydrate as a substrate. -!- Its physiological role is to convert the (R) forms to the (S) forms, which could then be restored to active dinucleotides by EC 4.2.1.93.
4.2.1.136
ADP-dependent NAD(P)H-hydrate dehydratase.
based on mapping to UniProt Q9X024
(1) ADP + (6S)-6-beta-hydroxy-1,4,5,6-tetrahydronicotinamide adenine- dinucleotide = AMP + phosphate + NADH. (2) ADP + (6S)-6-beta-hydroxy-1,4,5,6-tetrahydronicotinamide adenine- dinucleotide phosphate = AMP + phosphate + NADPH.
-!- Acts equally well on hydrated NADH and hydrated NADPH. -!- NAD(P)H spontaneously hydrates to both the (6S)- and (6R)- isomers. -!- The enzyme from bacteria consists of two domains, one of which acts as an NAD(P)H-hydrate epimerase that interconverts the two isomers to a 60:40 ratio (cf. EC 5.1.99.6), while the other catalyzes the dehydration. -!- Hence the enzyme can restore the complete mixture of isomers into NAD(P)H. -!- The enzyme has no activity with ATP, contrary to the enzyme from eukaryotes (cf. EC 4.2.1.93).

UniProtKB Entries (1)

Q9X024
NNR_THEMA
Thermotoga maritima MSB8
Bifunctional NAD(P)H-hydrate repair enzyme Nnr

PDB Structure

PDB 2AX3
External Links
Method X-RAY DIFFRACTION
Organism Escherichia
Primary Citation
Crystal structure of hypothetical protein (tm0922) from THERMOTOGA MARITIMA at 2.27 A resolution
Joint Center for Structural Genomics (JCSG)
To be published