Download MendeleyA New Arrangement of (beta/alpha)8 Barrels in the Synthase Subunit of PLP Synthase.
Zhu, J., Burgner, J.W., Harms, E., Belitsky, B.R., Smith, J.L.(2005) J Biol Chem 280: 27914-27923
- PubMed: 15911615
- DOI: https://doi.org/10.1074/jbc.M503642200
- Primary Citation of Related Structures:
1ZNN - PubMed Abstract:
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.
Organizational Affiliation:
Department of Biological Sciences, Purdue University, West Lafayette, Indiana 47907, USA.
