Bifunctional lysine ketoglutarate reductase /saccharopine dehydrogenase protein is a pair of enzymes linked on a single polypeptide chain that catalyze the initial, consecutive steps of lysine degradation. These proteins are related to the 2-domain saccharopine dehydrogenases. Along with formate dehydrogenase and similar enzymes, SDH consists paired domains resembling Rossmann folds in which the NAD-binding domain is inserted within the linear sequence of the catalytic domain. In this bifunctional enzyme, the LKR domain is N-terminal of the SDH domain. These proteins have a close match to the active site motif of SDHs, and an NAD-binding site motif that is a partial match to that found in SDH and other FDH-related proteins.
Feature 1:putative NAD(P) binding site [chemical binding site]
Evidence:
Comment:GxGxx[GSDA] motif resembles GxGxxG(17-18x)D, the characteristic NAD binding site motif of FHD-like proteins
Comment:based on comparison to L-Alanine Dehydrogenase and related proteins with structures containing bound NAD(P) or derivatives (contacts defined at 4A)
Jiyao W et al.(2023). "The conserved domain database in 2023.",