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PDBsum entry 1eq9
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* Residue conservation analysis
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Enzyme class:
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E.C.3.4.21.1
- chymotrypsin.
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Reaction:
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Preferential cleavage: Tyr-|-Xaa, Trp-|-Xaa, Phe-|-Xaa, Leu-|-Xaa.
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DOI no:
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J Mol Biol
298:895-901
(2000)
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PubMed id:
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The structure of an insect chymotrypsin.
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I.Botos,
E.Meyer,
M.Nguyen,
S.M.Swanson,
J.M.Koomen,
D.H.Russell,
E.F.Meyer.
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ABSTRACT
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The South American imported fire ant (Solenopsis invicta), without natural
enemies in the United States, widely infests the southern United States, causing
more than a half billion dollars in health and agriculture-related damage
annually in Texas alone. Fire ants are resistant to most insecticides, so
control will require a more fundamental understanding of their biochemistry and
metabolism leading to the design of selective, ecologically safe insecticides.
The 4th instar larvae play a crucial role in the nutrition of the colony by
secreting proteinases (especially chymotrypsin) which digest food products for
the entire colony. The first structure of an ant proteolytic enzyme, fire ant
chymotrypsin, was determined to atomic resolution (1.7 A). A structural
comparison of the ant and mammalian structures confirms the
"universality" of the serine proteinase motif and reveals a difference
at residues 147-148, which are proteolytically removed in the bovine enzyme but
are firmly intact in the ant chymotrypsin, suggesting a different activation
mechanism for the latter. Likewise, the absence of the covalently attached
propeptide domain (1-15) further suggests an uncharacteristic activation
mechanism. The presence of Gly189 in the S1 site is an atypical feature of this
chymotrypsin and is comparable only to human leukocyte elastase, hornet
chymotrypsin and fiddler crab collagenase. Binding studies confirm the
chymotrypsin nature of this novel enzyme.
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Selected figure(s)
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Figure 1.
Figure 1. Structure of fire ant chymotrypsin C1. Stereo
view of the 1.7 Å resolution structure of C1 superimposed
on bovine aC (root mean square deviation 5.4 Å) shows the
structural similarities and differences of their peptide
scaffolds. The active site tetrad is shown, the aC propeptide is
blue; peptide substrates bind from left (N terminus) to right.
The arrowhead points to the backbone of residues 147-148. All
structural Figures were created using program SPOCK [Christopher
1998].
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Figure 3.
Figure 3. Omit F[o] - F[c] map of the catalytic residues
contoured at 2.5s shows the strong, covalent binding of the
inhibitor, PMSF. The orientation of Figure 1 is retained.
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The above figures are
reprinted
by permission from Elsevier:
J Mol Biol
(2000,
298,
895-901)
copyright 2000.
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Figures were
selected
by an automated process.
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Literature references that cite this PDB file's key reference
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PubMed id
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Reference
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E.Mancini,
F.Tammaro,
F.Baldini,
A.Via,
D.Raimondo,
P.George,
P.Audisio,
I.V.Sharakhov,
A.Tramontano,
F.Catteruccia,
and
A.della Torre
(2011).
Molecular evolution of a gene cluster of serine proteases expressed in the Anopheles gambiae female reproductive tract.
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BMC Evol Biol,
11,
72.
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P.Attri,
P.Venkatesu,
and
A.Kumar
(2011).
Activity and stability of α-chymotrypsin in biocompatible ionic liquids: enzyme refolding by triethyl ammonium acetate.
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Phys Chem Chem Phys,
13,
2788-2796.
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Q.Zhan,
S.Zheng,
Q.Feng,
and
L.Liu
(2011).
A midgut-specific chymotrypsin cDNA (Slctlp1) from Spodoptera litura: cloning, characterization, localization and expression analysis.
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Arch Insect Biochem Physiol,
76,
130-143.
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B.Y.Chen,
and
B.Honig
(2010).
VASP: a volumetric analysis of surface properties yields insights into protein-ligand binding specificity.
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PLoS Comput Biol,
6,
0.
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A.R.Lopes,
P.M.Sato,
and
W.R.Terra
(2009).
Insect chymotrypsins: chloromethyl ketone inactivation and substrate specificity relative to possible coevolutional adaptation of insects and plants.
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Arch Insect Biochem Physiol,
70,
188-203.
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A.Srinivasan,
A.P.Giri,
and
V.S.Gupta
(2006).
Structural and functional diversities in lepidopteran serine proteases.
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Cell Mol Biol Lett,
11,
132-154.
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B.S.Coates,
R.L.Hellmich,
and
L.C.Lewis
(2006).
Sequence variation in trypsin- and chymotrypsin-like cDNAs from the midgut of Ostrinia nubilalis: methods for allelic differentiation of candidate Bacillus thuringiensis resistance genes.
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Insect Mol Biol,
15,
13-24.
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S.Herrero,
E.Combes,
M.M.Van Oers,
J.M.Vlak,
R.A.de Maagd,
and
J.Beekwilder
(2005).
Identification and recombinant expression of a novel chymotrypsin from Spodoptera exigua.
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Insect Biochem Mol Biol,
35,
1073-1082.
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A.Roussel,
M.Mathieu,
A.Dobbs,
B.Luu,
C.Cambillau,
and
C.Kellenberger
(2001).
Complexation of two proteic insect inhibitors to the active site of chymotrypsin suggests decoupled roles for binding and selectivity.
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J Biol Chem,
276,
38893-38898.
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PDB codes:
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J.Rotonda,
M.Garcia-Calvo,
H.G.Bull,
W.M.Geissler,
B.M.McKeever,
C.A.Willoughby,
N.A.Thornberry,
and
J.W.Becker
(2001).
The three-dimensional structure of human granzyme B compared to caspase-3, key mediators of cell death with cleavage specificity for aspartic acid in P1.
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Chem Biol,
8,
357-368.
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PDB code:
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The most recent references are shown first.
Citation data come partly from CiteXplore and partly
from an automated harvesting procedure. Note that this is likely to be
only a partial list as not all journals are covered by
either method. However, we are continually building up the citation data
so more and more references will be included with time.
Where a reference describes a PDB structure, the PDB
codes are
shown on the right.
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Links
