?
 
D-Erythronate-4-Phosphate Dehydrogenase NAD-binding and catalytic domains D-Erythronate-4-phosphate Dehydrogenase (E. coli gene PdxB), a D-specific 2-hydroxyacid dehydrogenase family member, catalyzes the NAD-dependent oxidation of erythronate-4-phosphate, which is followed by transamination to form 4-hydroxy-L-threonine-4-phosphate within the de novo biosynthesis pathway of vitamin B6. D-Erythronate-4-phosphate dehydrogenase has the common architecture shared with D-isomer specific 2-hydroxyacid dehydrogenases but contains an additional C-terminal dimerization domain in addition to an NAD-binding domain and the "lid" domain. The lid domain corresponds to the catalytic domain of phosphoglycerate dehydrogenase and other proteins of the D-isomer specific 2-hydroxyacid dehydrogenase family, which include groups such as formate dehydrogenase, glycerate dehydrogenase, L-alanine dehydrogenase, and S-adenosylhomocysteine hydrolase. Despite often low sequence identity, these proteins typically have a characteristic arrangement of 2 similar subdomains of the alpha/beta Rossmann fold NAD+ binding form. The NAD+ binding domain is inserted within the linear sequence of the mostly N-terminal catalytic domain, which has a similar domain structure to the internal NAD binding domain. Structurally, these domains are connected by extended alpha helices and create a cleft in which NAD is bound, primarily to the C-terminal portion of the 2nd (internal) domain. Some related proteins have similar structural subdomain but with a tandem arrangement of the catalytic and NAD-binding subdomains in the linear sequence. |
Jiyao W et al.(2023). "The conserved domain database in 2023.",