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PDBsum entry 2ctc
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HydrolasE(C-terminal peptidase)
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PDB id
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2ctc
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References listed in PDB file
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Key reference
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Title
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High-Resolution structure of the complex between carboxypeptidase a and l-Phenyl lactate.
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Authors
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A.Teplyakov,
K.S.Wilson,
P.Orioli,
S.Mangani.
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Ref.
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Acta Crystallogr D Biol Crystallogr, 1993,
49,
534-540.
[DOI no: ]
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PubMed id
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Abstract
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The X-ray structures of native carboxypeptidase A and of the enzyme-inhibitor
complex with L-phenyl lactate have been refined at 1.54 and 1.45 A resolution to
R factors of 0.151 and 0.161, respectively. Crystals of the complex were
isomorphous with the native crystals (space group P2(1), a = 51.60, b = 60.27, c
= 47.25 A, beta = 97.27 degrees ). The high-resolution electron density allowed
correction of many side-chain positions in the classical carboxypeptidase A
model. This reflects the advantages of the high-quality complete synchrotron
data collected with an imaging plate detector. The conformational changes in the
active centre of the enzyme upon binding of the inhibitor are restricted to only
two residues, Tyr248 and Arg145. L-Phenyl lactate is bound in the S1' pocket and
forms hydrogen bonds to Arg145, Glu270 and to the zinc-bound water molecule. The
present structure provides an explanation for the higher stability of the
complexes with the products of esterolysis in comparison with those of
amidolysis. This is consistent with the finding that product release is rate
limiting for esters but not for peptides.
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Figure 2.
Fig. 2. The ~o/~ plot for the native CPA model.
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Figure 3.
Fig. 3. Representaive fragment of the (3Fo 2Fc) lectron density of CPA contoured at the level of 1.Str, where o is the
rootmeansquare deviation. The present CPA model is shown in green, the 5CPA odel is shown in orange. (a) Ser254 and Ile255; (b)
Leu271 and Tyr238 with the hydrogenbonded water molecule.
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The above figures are
reprinted
by permission from the IUCr:
Acta Crystallogr D Biol Crystallogr
(1993,
49,
534-540)
copyright 1993.
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