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PDBsum entry 4fiq
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References listed in PDB file
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Key reference
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Title
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Crystal structure of pyridoxal biosynthesis lyase pdxs from pyrococcus horikoshii.
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Authors
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A.Matsuura,
J.Y.Yoon,
H.J.Yoon,
H.H.Lee,
S.W.Suh.
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Ref.
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Mol Cells, 2012,
34,
407-412.
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PubMed id
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Abstract
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Pyridoxal 5'-phosphate (PLP) is the biologically active form of vitamin B(6) and
is de novo synthesized from three substrates, dihydroxyacetone phosphate (DHAP),
riburose 5-phosphate (RBP), and ammonia hydrolysed from glutamine. Glutamine
amidotransferase (PdxT) catalyzes the production of ammonia from glutamine,
while PdxS catalyzes the following condensation of ribulose 5-phosphate (Ru5P),
glyceraldehyde-3-phosphate (G3P), and ammonia. PdxS exists as a hexamer or
dodecamer depending on species and makes a 1:1 complex with PdxT. Pyrococcus
horikoshii PdxS has a 37 amino acids insertion region, which is found in some
archaeal PdxS proteins, but its structure and function are unknown. To provide
further structural information on the role of the insertion region, the
oligomeric state, and ligand binding mode of P. horikoshii PdxS, the crystal
structure of PdxS from P. horikoshii was solved in two forms: (i) apo form, (ii)
r ibose 5-phosphate (R5P) complex and the quaternary structure of PdxS in
solution was determined by analytical gel filtration. P. horikoshii PdxS forms
hexamer in solution based on analytical gel filtration data. When we superimpose
the structure of P. horikoshii PdxS with other dodecamer structures of PdxS, the
additional insertion is located apart from the active site and induces a steric
clash on the hexamer-hexamer interface of PdxS proteins. Our results suggest
that the additional insertion perturbs dodecamer formation of P. horikoshii PdxS.
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