HMM Summary Page: TIGR01532

Functionerythrose-4-phosphate dehydrogenase
Gene Symbolepd
Trusted Cutoff530.55
Domain Trusted Cutoff530.55
Noise Cutoff455.25
Domain Noise Cutoff455.25
Isology Typeequivalog
EC Number1.2.1.72
HMM Length325
Mainrole CategoryBiosynthesis of cofactors, prosthetic groups, and carriers
Subrole CategoryPyridoxine
Gene Ontology TermGO:0008615: pyridoxine biosynthetic process biological_process
GO:0048001: erythrose-4-phosphate dehydrogenase activity molecular_function
AuthorSelengut J
Entry DateJun 5 2002 3:17PM
Last ModifiedFeb 14 2011 3:27PM
CommentThis HMM represents the small clade of dehydrogenases in gamma-proteobacteria which utilize NAD+ to oxidize erythrose-4-phosphate (E4P) to 4-phospho-erythronate, a precursor for the de novo synthesis of pyridoxine via 4-hydroxythreonine and D-1-deoxyxylulose [1]. This enzyme activity appears to have evolved from glyceraldehyde-3-phosphate dehydrogenase, whose substrate differs only in the lack of one carbon relative to E4P. Accordingly, this model is very close to the corresponding models for GAPDH, and those sequences which hit above trusted here invariably hit between trusted and noise to the GAPDH model (TIGR01534). Similarly, it may be found that there are species outside of the gamma proteobacteria which synthesize pyridoxine and have more than one aparrent GAPDH gene of which one may have E4PD activity - this may necessitate a readjustment of these models. Alternatively, some of the GAPDH enzymes may prove to be bifunctional in certain species.
ReferencesRN [1] RM PMID: 7751290 RT Biochemical characterization of gapB-encoded erythrose 4-phosphate dehydrogenase of Escherichia coli K-12 and its possible role in pyridoxal 5'-phosphate biosynthesis. RA Zhao G, Pease AJ, Bharani N, Winkler ME. RL J Bacteriol. 1995 May;177(10):2804-12. DR HAMAP; MF_01640; 55 of 58