1ZNN: Structure Of The Synthase Subunit Of Plp Synthase

Pyridoxal 5'-phosphate (PLP, vitamin B6), a cofactor in many enzymatic reactions, has two distinct biosynthetic routes, which do not coexist in any organism. Two proteins, known as PdxS and PdxT, together form a PLP synthase in plants, fungi, archaea, and some eubacteria. PLP synthase is a heteromeric glutamine amidotransferase in which PdxT produces ammonia from glutamine and PdxS combines ammonia with five- and three-carbon phosphosugars to form PLP. In the 2.2-A crystal structure, PdxS is a cylindrical dodecamer of subunits having the classic (beta/alpha)8 barrel fold. PdxS subunits form two hexameric rings with the active sites positioned on the inside. The hexamer and dodecamer forms coexist in solution. A novel phosphate-binding site is suggested by bound sulfate. The sulfate and another bound molecule, methyl pentanediol, were used to model the substrate ribulose 5-phosphate, and to propose catalytic roles for residues in the active site. The distribution of conserved surfaces in the PdxS dodecamer was used to predict a docking site for the glutaminase partner, PdxT.
PDB ID: 1ZNNDownload
MMDB ID: 33273
PDB Deposition Date: 2005/5/11
Updated in MMDB: 2012/11
Experimental Method:
x-ray diffraction
Resolution: 2.2  Å
Source Organism:
Similar Structures:
Biological Unit for 1ZNN: dodecameric; determined by author and by software (PISA,PQS)
Molecular Components in 1ZNN
Label Count Molecule
Proteins (12 molecules)
PLP Synthase
Molecule annotation
Chemicals (36 molecules)
* Click molecule labels to explore molecular sequence information.

Citing MMDB