1G77: X-ray Structure Of Escherichia Coli Pyridoxine 5`-phosphate Oxidase Complexed With Pyridoxal 5'-phosphate At 2.0 A Resolution

Escherichia coli pyridoxine 5'-phosphate oxidase catalyzes the terminal step in the biosynthesis of pyridoxal 5'-phosphate by the FMN oxidation of pyridoxine 5'-phosphate forming FMNH(2) and H(2)O(2). Recent studies have shown that in addition to the active site, pyridoxine 5'-phosphate oxidase contains a non-catalytic site that binds pyridoxal 5'-phosphate tightly. The crystal structure of pyridoxine 5'-phosphate oxidase from E. coli with one or two molecules of pyridoxal 5'-phosphate bound to each monomer has been determined to 2.0 A resolution. One of the pyridoxal 5'-phosphate molecules is clearly bound at the active site with the aldehyde at C4' of pyridoxal 5'-phosphate near N5 of the bound FMN. A protein conformational change has occurred that partially closes the active site. The orientation of the bound pyridoxal 5'-phosphate suggests that the enzyme catalyzes a hydride ion transfer between C4' of pyridoxal 5'-phosphate and N5 of FMN. When the crystals are soaked with excess pyridoxal 5'-phosphate an additional molecule of this cofactor is also bound about 11 A from the active site. A possible tunnel exists between the two sites so that pyridoxal 5'-phosphate formed at the active site may transfer to the non-catalytic site without passing though the solvent.
PDB ID: 1G77Download
MMDB ID: 14484
PDB Deposition Date: 2000/11/9
Updated in MMDB: 2000/12
Experimental Method:
x-ray diffraction
Resolution: 2.1  Å
Source Organism:
Similar Structures:
Biological Unit for 1G77: dimeric; determined by author and by software (PISA,PQS)
Molecular Components in 1G77
Label Count Molecule
Proteins (2 molecules)
Pyridoxine 5`-phosphate Oxidase
Molecule annotation
Chemicals (8 molecules)
* Click molecule labels to explore molecular sequence information.

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