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PDBsum entry 1m7y
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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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Apple 1-Aminocyclopropane-1-Carboxylate synthase in complex with the inhibitor l-Aminoethoxyvinylglycine. Evidence for a ketimine intermediate.
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Authors
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G.Capitani,
D.L.Mccarthy,
H.Gut,
M.G.Grütter,
J.F.Kirsch.
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Ref.
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J Biol Chem, 2002,
277,
49735-49742.
[DOI no: ]
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PubMed id
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Abstract
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The 1.6-A crystal structure of the covalent ketimine complex of apple
1-aminocyclopropane-1-carboxylate (ACC) synthase with the potent inhibitor
l-aminoethoxyvinylglycine (AVG) is described. ACC synthase catalyzes the
committed step in the biosynthesis of ethylene, a plant hormone that is
responsible for the initiation of fruit ripening and for regulating many other
developmental processes. AVG is widely used in plant physiology studies to
inhibit the activity of ACC synthase. The structural assignment is supported by
the fact that the complex absorbs maximally at 341 nm. These results are not in
accord with the recently reported crystal structure of the tomato ACC synthase
AVG complex, which claims that the inhibitor only associates noncovalently. The
rate constant for the association of AVG with apple ACC synthase was determined
by stopped-flow spectrophotometry (2.1 x 10(5) m(-1) s(-1)) and by the rate of
loss of enzyme activity (1.1 x 10(5) m(-1) s(-1)). The dissociation rate
constant determined by activity recovery is 2.4 x 10(-6) s(-1). Thus, the
calculated K(d) value is 10-20 pm.
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Figure 6.
Fig. 6. A, superposition of the active sites of
unliganded (sea green) and AVG-bound (yellow) ACC synthase. Only
selected residues are shown. B, the active sites of AVG-bound
ACC synthase (gray) and cystathionine  -lyase (sea
green). C, the C  traces of
unliganded (yellow) and AVG-bound (blue) ACC synthase. This
illustration was prepared with DINO.
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Figure 7.
Fig. 7. LIGPLOT (13) representation of the hydrogen
bonding between ACC synthase and the AVG·PLP adduct.
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The above figures are
reprinted
by permission from the ASBMB:
J Biol Chem
(2002,
277,
49735-49742)
copyright 2002.
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