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PDBsum entry 1jsc
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Contents |
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* Residue conservation analysis
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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 yeast acetohydroxyacid synthase: a target for herbicidal inhibitors.
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Authors
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S.S.Pang,
R.G.Duggleby,
L.W.Guddat.
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Ref.
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J Mol Biol, 2002,
317,
249-262.
[DOI no: ]
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PubMed id
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Abstract
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Acetohydroxyacid synthase (AHAS; EC 4.1.3.18) catalyzes the first step in
branched-chain amino acid biosynthesis. The enzyme requires thiamin diphosphate
and FAD for activity, but the latter is unexpected, because the reaction
involves no oxidation or reduction. Due to its presence in plants, AHAS is a
target for sulfonylurea and imidazolinone herbicides. Here, the crystal
structure to 2.6 A resolution of the catalytic subunit of yeast AHAS is
reported. The active site is located at the dimer interface and is near the
proposed herbicide-binding site. The conformation of FAD and its position in the
active site are defined. The structure of AHAS provides a starting point for the
rational design of new herbicides.
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Figure 7.
Figure 7. (a) A schematic diagram illustrating the residues
contacting the ThDP molecule. (b) View of the active site
showing the relative locations of ThDP, Mg2+ and the flavin ring
of FAD in the dimer interface of yeast AHAS. (c) Contacts
between AHAS, ThDP and Mg2+. Coordination distances shown as
broken lines to Mg2+ are in the range 2.0-2.3 Å.
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Figure 9.
Figure 9. Proposed interaction of AHAS and the herbicidal
inhibitor, imazapyr, which was docked into the enzyme using the
program GOLD. [37] Amino acid residues at herbicide-resistance
sites are labeled and shown as CPK models.
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The above figures are
reprinted
by permission from Elsevier:
J Mol Biol
(2002,
317,
249-262)
copyright 2002.
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