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PDBsum entry 1iav
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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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Engineered bacillus lentus subtilisins having altered flexibility.
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Authors
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T.Graycar,
M.Knapp,
G.Ganshaw,
J.Dauberman,
R.Bott.
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Ref.
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J Mol Biol, 1999,
292,
97.
[DOI no: ]
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PubMed id
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Abstract
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The three-dimensional structures of engineered variants of Bacillus lentus
subtilisin having increased enzymatic activity, K27R/N87S/V104Y/N123S/T274A
(RSYSA) and N76D/N87S/S103A/V104I (DSAI), were determined by X-ray
crystallography. In addition to identifying changes in atomic position we report
a method that identifies protein segments having altered flexibility. The method
utilizes a statistical analysis of variance to delineate main-chain temperature
factors that represent significant departures from the overall variance between
equivalent regions seen throughout the structure. This method reveals changes in
main-chain mobility in both variants. Residues 125-127 have increased mobility
in the RSYSA variant while residues 100-104 have decreased mobility in the DSAI
variant. These segments are located at the substrate-binding site and changes in
their mobility are believed to relate to the observed changes in proteolytic
activity. The effect of altered crystal lattice contacts on segment flexibility
becomes apparent when identical variants, determined in two crystal forms, are
compared with the native enzyme.
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Figure 3.
Figure 3. Stereo diagram showing 2 F[o] -F[c]electron
density map for the catalytic triad of RSYSA(I) contoured at 1s.
The density for Ser125 is discontinuous in the electron density
map of RSYSA(I) in contrast to the native density shown in
Figure 1.
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Figure 6.
Figure 6. Stereo diagram showing 2 F[o] -F[c]electron
density map for the catalytic triad of DSAI. Partial density is
observed for PMSF suggesting that the phenyl moiety is
disordered. The side-chain of His is again oriented away from
Ser221.
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The above figures are
reprinted
by permission from Elsevier:
J Mol Biol
(1999,
292,
97-0)
copyright 1999.
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