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PDBsum entry 2fs2
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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, Function, And mechanism of the phenylacetate pathway hot dog-Fold thioesterase paai.
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Authors
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F.Song,
Z.Zhuang,
L.Finci,
D.Dunaway-Mariano,
R.Kniewel,
J.A.Buglino,
V.Solorzano,
J.Wu,
C.D.Lima.
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Ref.
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J Biol Chem, 2006,
281,
11028-11038.
[DOI no: ]
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PubMed id
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Abstract
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The structure and biochemical function of the hot dog-fold thioesterase PaaI
operative in the aerobic phenylacetate degradation pathway are examined. PaaI
showed modest activity with phenylacetyl-coenzyme A, suggestive of a role in
coenzyme A release from this pathway intermediate in the event of limiting
downstream pathway enzymes. Minimal activity was observed with aliphatic
acyl-coenzyme A thioesters, which ruled out PaaI function in the lower
phenylacetate pathway. PaaI was most active with ring-hydroxylated
phenylacetyl-coenzyme A thioesters. The x-ray crystal structure of the
Escherichia coli thioesterase is reported and analyzed to define the structural
basis of substrate recognition and catalysis. The contributions of catalytic and
substrate binding residues, thus, identified were examined through steady-state
kinetic analysis of site-directed mutant proteins.
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Figure 1.
FIGURE 1. The outline of a model of the phenylacetate
pathway common to E. coli and A. evansii. 2-Hydroxyphenylacetate
is isolated from the mutant lacking an active ring-opening
enzyme (PaaG).
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Figure 6.
FIGURE 6. Electrostatic surface picture illustrating the
solvent exposure of E. coli PaaI active site. The active site is
identified by the 4-hydroxyphenacyl-CoA ligand (yellow), which
was positioned by superpositioning the PaaI structure with the
structure of the Arthrobacter 4-HBA-CoA thioesterase
(4-hydroxyphenacyl-CoA) complex (PDB code 1Q4T [PDB]
) (40). The picture was generated using the graphics program
Pymol (69).
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The above figures are
reprinted
by permission from the ASBMB:
J Biol Chem
(2006,
281,
11028-11038)
copyright 2006.
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