1nuc: Difference between revisions

Revision as of 15:10, 21 February 2008

STAPHYLOCOCCAL NUCLEASE, V23C VARIANT

OverviewOverview

The structures of several variants of staphylococcal nuclease with long flexible unnatural amino acid side chains in the hydrophobic core have been determined by X-ray crystallography. The unnatural amino acids are disulfide moieties between the lone cysteine residue in V23C nuclease and methane, ethane, 1-n-propane, 1-n-butane, 1-n-pentane, and 2-hydroxyethyl thiols. We have examined changes in the core packing of these mutants. Side chains as large as the 1-n-propyl cysteine disulfide can be incorporated without perturbation of the structure. This is due, in part, to cavities present in the wild-type protein. The longest side chains are not well defined, even though they remain buried within the protein interior. These results suggest that the enthalpy-entropy balance that governs the rigidity of protein interiors favors tight packing only weakly. Additionally, the tight packing observed normally in protein interiors may reflect, in part, the limited numbers of rotamers available to the natural amino acids.

About this StructureAbout this Structure

1NUC is a Single protein structure of sequence from Staphylococcus aureus with and as ligands. Active as Micrococcal nuclease, with EC number 3.1.31.1 Full crystallographic information is available from OCA.

ReferenceReference

Mobile unnatural amino acid side chains in the core of staphylococcal nuclease., Wynn R, Harkins PC, Richards FM, Fox RO, Protein Sci. 1996 Jun;5(6):1026-31. PMID:8762134

Page seeded by OCA on Thu Feb 21 14:10:03 2008

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OCA

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-[[Image:1nuc.gif|left|200px]]<br /><applet load="1nuc" size="450" color="white" frame="true" align="right" spinBox="true"
+[[Image:1nuc.gif|left|200px]]<br /><applet load="1nuc" size="350" color="white" frame="true" align="right" spinBox="true"
 caption="1nuc, resolution 1.9&Aring;" />
 '''STAPHYLOCOCCAL NUCLEASE, V23C VARIANT'''<br />
 ==Overview==
-The structures of several variants of staphylococcal nuclease with long, flexible unnatural amino acid side chains in the hydrophobic core have, been determined by X-ray crystallography. The unnatural amino acids are, disulfide moieties between the lone cysteine residue in V23C nuclease and, methane, ethane, 1-n-propane, 1-n-butane, 1-n-pentane, and 2-hydroxyethyl, thiols. We have examined changes in the core packing of these mutants., Side chains as large as the 1-n-propyl cysteine disulfide can be, incorporated without perturbation of the structure. This is due, in part, to cavities present in the wild-type protein. The longest side chains are, not well defined, even though they remain buried within the protein, interior. These results suggest that the enthalpy-entropy balance that, governs the rigidity of protein interiors favors tight packing only, weakly. Additionally, the tight packing observed normally in protein, interiors may reflect, in part, the limited numbers of rotamers available, to the natural amino acids.
+The structures of several variants of staphylococcal nuclease with long flexible unnatural amino acid side chains in the hydrophobic core have been determined by X-ray crystallography. The unnatural amino acids are disulfide moieties between the lone cysteine residue in V23C nuclease and methane, ethane, 1-n-propane, 1-n-butane, 1-n-pentane, and 2-hydroxyethyl thiols. We have examined changes in the core packing of these mutants. Side chains as large as the 1-n-propyl cysteine disulfide can be incorporated without perturbation of the structure. This is due, in part, to cavities present in the wild-type protein. The longest side chains are not well defined, even though they remain buried within the protein interior. These results suggest that the enthalpy-entropy balance that governs the rigidity of protein interiors favors tight packing only weakly. Additionally, the tight packing observed normally in protein interiors may reflect, in part, the limited numbers of rotamers available to the natural amino acids.
 ==About this Structure==
-NUC is a [http://en.wikipedia.org/wiki/Single_protein Single protein] structure of sequence from [http://en.wikipedia.org/wiki/Staphylococcus_aureus Staphylococcus aureus] with CA and THP as [http://en.wikipedia.org/wiki/ligands ligands]. Active as [http://en.wikipedia.org/wiki/Micrococcal_nuclease Micrococcal nuclease], with EC number [http://www.brenda-enzymes.info/php/result_flat.php4?ecno=3.1.31.1 3.1.31.1] Full crystallographic information is available from [http://ispc.weizmann.ac.il/oca-bin/ocashort?id=1NUC OCA].
+NUC is a [http://en.wikipedia.org/wiki/Single_protein Single protein] structure of sequence from [http://en.wikipedia.org/wiki/Staphylococcus_aureus Staphylococcus aureus] with <scene name='pdbligand=CA:'>CA</scene> and <scene name='pdbligand=THP:'>THP</scene> as [http://en.wikipedia.org/wiki/ligands ligands]. Active as [http://en.wikipedia.org/wiki/Micrococcal_nuclease Micrococcal nuclease], with EC number [http://www.brenda-enzymes.info/php/result_flat.php4?ecno=3.1.31.1 3.1.31.1] Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=1NUC OCA].
 ==Reference==
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 [[Category: Single protein]]
 [[Category: Staphylococcus aureus]]
-[[Category: Fox, R.O.]]
+[[Category: Fox, R O.]]
-[[Category: Harkins, P.C.]]
+[[Category: Harkins, P C.]]
-[[Category: Richards, F.M.]]
+[[Category: Richards, F M.]]
 [[Category: Wynn, R.]]
 [[Category: CA]]
@@ Line 22: / Line 22: @@
 [[Category: nuclease]]
-''Page seeded by [http://ispc.weizmann.ac.il/oca OCA ] on Tue Nov 20 22:33:52 2007''
+''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Thu Feb 21 14:10:03 2008''