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PDBsum entry 1ynu
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References listed in PDB file
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Key reference
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Title
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Structure of acc synthase inactivated by the mechanism-Based inhibitor l-Vinylglycine.
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Authors
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G.Capitani,
M.Tschopp,
A.C.Eliot,
J.F.Kirsch,
M.G.Grütter.
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Ref.
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FEBS Lett, 2005,
579,
2458-2462.
[DOI no: ]
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PubMed id
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Abstract
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L-Vinylglycine (L-VG) is both a substrate for and a mechanism-based inhibitor of
1-aminocyclopropane-1-carboxylate (ACC) synthase. The ratio of the rate
constants for catalytic conversion to alpha-ketobutyrate and ammonia to
inactivation is 500/1. The crystal structure of the covalent adduct of the
inactivated enzyme was determined at 2.25 Angstroms resolution. The active site
contains an external aldimine of the adduct of L-VG with the pyridoxal
5'-phosphate cofactor. The side chain gamma-carbon of L-VG is covalently bound
to the epsilon-amino group of Lys273. This species corresponds to one of the two
alternatives proposed by Feng and Kirsch [Feng, L. and Kirsch, J.F. (2000)
L-Vinylglycine is an alternative substrate as well as a mechanism-based
inhibitor of 1-aminocyclopropane-1-carboxylate synthase. Biochemistry 39,
and presumably results from Michael addition to a vinylglycine
ketimine intermediate.
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Figure 1.
Fig. 1. Schematic summary of the reactions of ACC synthase
with the inhibitors AVG and AMA. Prepared with ChemDraw.
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Figure 2.
Fig. 2. Schematic summary of the ACC synthase-catalyzed
reactions with the natural substrate, SAM and with l-VG.
Prepared with ChemDraw.
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The above figures are
reprinted
by permission from the Federation of European Biochemical Societies:
FEBS Lett
(2005,
579,
2458-2462)
copyright 2005.
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