Function
Involved in the biosynthesis of forosamine ((4-dimethylamino)-2,3,4,6-tetradeoxy-alpha-D-threo-hexopyranose), a highly deoxygenated sugar component of several bioactive natural products such as the insecticidal spinosyns A and D (PubMed:11358695, PubMed:18345667). Catalyzes C-3 deoxygenation of dTDP-4-keto-2,6-dideoxy-alpha-D-glucose to yield dTDP-4-keto-2,3,6-trideoxy-D-glucose via a combined transamination-deoxygenation reaction (PubMed:18345667). The catalysis is initiated by a transamination step in which pyridoxal 5'-phosphate (PLP) is converted to pyridoxamine 5'-phosphate (PMP) in the presence of L-glutamate (PubMed:18345667). This coenzyme then forms a Schiff base with dTDP-4-keto-2,6-dideoxy-alpha-D-glucose and the resulting adduct undergoes a PMP-mediated beta-dehydration reaction to give a sugar enamine intermediate, which after a 2 electrons reduction and hydrolysis yields dTDP-4-keto-2,3,6-trideoxy-D-glucose as a product (PubMed:18345667). Requires cellular reductase (ferredoxin or flavodoxin reductase) rather than a specific partner reductase (PubMed:18345667). L-glutamate is 20-fold more efficient than L-aspartate as an amino donor (PubMed:18345667). In the absence of an electron source and in the presence of L-glutamate, catalyzes a transamination reaction, converting dTDP-4-keto-2,6-dideoxy-alpha-D-glucose to dTDP-4-amino-2,4,6-trideoxy-D-glucose (PubMed:18345667).
Sequence
MQSRKTRALGKGRARVTSCDDTCATATEMVPDAKDRILASVRDYHREQESPTFVAGSTPIRPSGAVLDEDDRVALVEAALELRIAAGGNARRFESEFARFFGLRKAHLVNSGSSANLLALSSLTSPKLGEARLRPGDEVITAAVGFPTTINPAVQNGLVPVFVDVELGTYNATPDRIKAAVTERTRAIMLAHTLGNPFAADEIAEIAKEHELFLVEDNCDAVGSTYRGRLTGTFGDLTTVSFYPAHHITSGEGGCVLTGSLELARIIESLRDWGRDCWCEPGVDNTCRKRFDYHLGTLPPGYDHKYTFSHVGYNLKTTDLQAALALSQLSKISAFGSARRRNWRRLREGLSGLPGLLLPVATPHSDPSWFGFAITISADAGFTRAALVNFLESRNIGTRLLFGGNITRHPAFEQVRYRIADALTNSDIVTDRTFWVGVYPGITDQMIDYVVESIAEFVAKSS