Pyridoxine 5'-phosphate oxidase C-terminal dimerisation region
This domain represents one of the two dimerisation regions of the protein, located at the edge of the dimer interface, at the C-terminus, being the last three beta strands, S6, S7, and S8 along with the last three residues to the end. In Swiss:P21159 ...
This domain represents one of the two dimerisation regions of the protein, located at the edge of the dimer interface, at the C-terminus, being the last three beta strands, S6, S7, and S8 along with the last three residues to the end. In Swiss:P21159, S6 runs from residues 178-192, S7 from 200-206 and S8 from 211-215. the extended loop, of residues 167-177 may well be involved in the pocket formed between the two dimers that positions the FMN molecule [1].To date, the only time functional oxidase or phenazine biosynthesis activities have been experimentally demonstrated is when the sequences contain both Pfam:PF01243 and Pfam:PF10590. It is unknown the role performed by each domain in bringing about molecular functions of either oxidase or phenazine activity [2].
This entry includes pyridoxamine 5'-phosphate oxidases, FMN flavoproteins that catalyse the oxidation of pyridoxamine-5-P (PMP) and pyridoxine-5-P (PNP) to pyridoxal-5-P (PLP). This reaction serves as the terminal step in the de novo biosynthesis of ...
This entry includes pyridoxamine 5'-phosphate oxidases, FMN flavoproteins that catalyse the oxidation of pyridoxamine-5-P (PMP) and pyridoxine-5-P (PNP) to pyridoxal-5-P (PLP). This reaction serves as the terminal step in the de novo biosynthesis of PLP in Escherichia coli and as a part of the salvage pathway of this coenzyme in both E. coli and mammalian cells [1-5]. The binding sites for FMN and for substrate have been highly conserved throughout evolution. In some species, the coenzyme F420 may perform the FMN role [7]. This entry represents the N-terminal segment of these proteins, which is involved in FMN binding when they form the dimer [5]. In human PNPO, it has been shown that this region contains some of the residues that constitute the PLP allosteric site which regulates its activity [4]. The C-terminal region of these proteins (Pfam:PF10590) is involved in dimerisation and also contributes some residues to the PLP allosteric site. Some of the members included in this entry are involved in phenazine biosynthesis [6].
Escherichia coli pyridoxine 5'-phosphate oxidase is the enzyme catalysing the final step in the synthesis of pyridoxal 5'-phosphate, a vital cofactor in many metabolic processes including amino acid metabolism. This means that the synthetic pathway is of great importance to the survival of the bacteria. The enzyme is also present in higher organisms, and the Escherichia coli form is expected to show significant sequence and structural homology to the mammalian form. Of particular interest is the second binding site of PLP which protects the product of the reaction from release into the cell so it can be transferred directly onto the enzymes that require it.
