Structural comparisons lead to the definition of a new superfamily of NAD(P)(H)-accepting oxidoreductases: the single-domain reductases/epimerases/dehydrogenases (the 'RED' family).
Using both primary- and tertiary-structure comparisons, we have established new structural similarities shared by reductases, epimerases and dehydrogenases not previously known to be related. Despite the low sequence identity (down to 10%), short consensus segments are identified. We show that the sequence, the active site and the supersecondary structure are well conserved in these proteins. New homologues (the protochlorophyllide reductases) are detected, and we define a new superfamily composed of single-domain dinucleotide-binding enzymes. Rules for the cofactor-binding specificity are deduced from our sequence alignment. The involvement of some amino acids in catalysis is discussed. Comparison with two-domain dehydrogenases allows us to distinguish two general mechanisms of divergent evolution.
Labesse
G
G
Laboratoire de Minéralogie-Cristallographie, Universités PVI et PVII, C.N.R.S. U.R.A. 09, Paris, France.
Vidal-Cros
A
A
Chomilier
J
J
Gaudry
M
M
Mornon
J P
JP
D000595:Amino Acid Sequence; D001665:Binding Sites; D008969:Molecular Sequence Data; D009245:NADH Dehydrogenase / Q000737:chemistry; D009247:NADH, NADPH Oxidoreductases / Q000737:chemistry*; D009252:NADPH Dehydrogenase / Q000737:chemistry; D017434:Protein Structure, Tertiary; D019998:Racemases and Epimerases / Q000737:chemistry*; D016415:Sequence Alignment; D013329:Structure-Activity Relationship
D009247:NADH, NADPH Oxidoreductases; D009252:NADPH Dehydrogenase; D009245:NADH Dehydrogenase; D019998:Racemases and Epimerases