1.1.1.3: homoserine dehydrogenase

This is an abbreviated version, for detailed information about homoserine dehydrogenase, go to the full flat file.

Reaction

L-homoserine
+
NAD(P)+
=
L-aspartate 4-semialdehyde
+
NAD(P)H
+
H+

Synonyms

AK-HDH, AK-HSD-1, AK-HSDH, aspartate kinase-homoserine dehydrogenase, aspartokinase-homoserine dehydrogenase I, HDH, hom, hom-1, Hom6, homoserine dehydrogenase 1, homoserine dehydrogenase 2, HSD, HSDH, HseDH, orf19.2951, SACOL1362

ECTree

     1 Oxidoreductases
         1.1 Acting on the CH-OH group of donors
             1.1.1 With NAD+ or NADP+ as acceptor
                1.1.1.3 homoserine dehydrogenase

Cofactor

Cofactor on EC 1.1.1.3 - homoserine dehydrogenase

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COFACTOR
ORGANISM
UNIPROT
COMMENTARY hide
LITERATURE
IMAGE
additional information
NADP does not act as a cofactor for this enzyme, but as a strong inhibitor of NAD+-dependent oxidation of Hse, analysis of the cofactor-binding site of the enzyme, Pyrococcus horikoshii HseDH shows a unique cofactor binding mode, which is not observed in conventional NAD(P)-dependent dehydrogenases. Superposition of the Hse/NADPH-bound K57A structure onto the NADPH-bound wild-type structure shows that the NADPH molecule in the mutant structure is positioned/configured nearly identically to the NADPH molecule in the wild-type structure, except for the positioning of the C2 phosphate group of the adenine ribose. The C2 phosphate is tightly held in position through five surrounding hydrogen bonds in the wild-type enzyme. In K57A mutant the C2 phosphate group is rotates in a clockwise direction around C2B of NADPH by about 30° relative to the wild-type structure. The guanidino group of Arg40 in the mutant is also rotated clockwise by about 90° around the NE atom of Arg40 relative to the wild-type structure
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