1tpw: Difference between revisions

Revision as of 16:16, 21 February 2008

TRIOSEPHOSPHATE ISOMERASE DRINKS WATER TO KEEP HEALTHY

OverviewOverview

The structural basis for the effect of the S96P mutation in chicken triosephosphate isomerase (cTIM) has been analyzed using a combination of X-ray crystallography and Fourier transform infrared spectroscopy. The X-ray structure is that of the enzyme complexed with phosphoglycolohydroxamate (PGH), an intermediate analogue, solved at a resolution of 1.9 A. The S96P mutation was identified as a second-site reverent when catalytically crippled mutants, E165D and H95N, were subjected to random mutagenesis. The presence of the second mutation leads to enhanced activity over the single mutation. However, the effect of the S96P mutation alone is to decrease the catalytic efficiency of the enzyme. The crystal structures of the S96P double mutants show that this bulky proline side chain alters the water structure within the active-site cavity (E165D; ref 1) and prevents nonproductive binding conformations of the substrate (H95N; ref 2). Comparison of the S96P single mutant structure with those of the wild-type cTIM, those of the single mutants (E165D and H95N), and those of the double mutants (E165D/S96P and H95N/S96P) begins to address the role of the conserved serine residue at this position. The results indicate that the residue positions the catalytic base E165 optimally for polarization of the substrate carbonyl, thereby aiding in proton abstraction. In addition, this residue is involved in positioning critical water molecules, thereby affecting the way in which water structure influences activity.

About this StructureAbout this Structure

1TPW is a Single protein structure of sequence from Gallus gallus with as ligand. Active as Triose-phosphate isomerase, with EC number 5.3.1.1 Full crystallographic information is available from OCA.

ReferenceReference

The role of water in the catalytic efficiency of triosephosphate isomerase., Zhang Z, Komives EA, Sugio S, Blacklow SC, Narayana N, Xuong NH, Stock AM, Petsko GA, Ringe D, Biochemistry. 1999 Apr 6;38(14):4389-97. PMID:10194358

Page seeded by OCA on Thu Feb 21 15:16:08 2008

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OCA

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-[[Image:1tpw.jpg|left|200px]]<br /><applet load="1tpw" size="450" color="white" frame="true" align="right" spinBox="true"
+[[Image:1tpw.jpg|left|200px]]<br /><applet load="1tpw" size="350" color="white" frame="true" align="right" spinBox="true"
 caption="1tpw, resolution 1.9&Aring;" />
 '''TRIOSEPHOSPHATE ISOMERASE DRINKS WATER TO KEEP HEALTHY'''<br />
 ==Overview==
-The structural basis for the effect of the S96P mutation in chicken, triosephosphate isomerase (cTIM) has been analyzed using a combination of, X-ray crystallography and Fourier transform infrared spectroscopy. The, X-ray structure is that of the enzyme complexed with, phosphoglycolohydroxamate (PGH), an intermediate analogue, solved at a, resolution of 1.9 A. The S96P mutation was identified as a second-site, reverent when catalytically crippled mutants, E165D and H95N, were, subjected to random mutagenesis. The presence of the second mutation leads, to enhanced activity over the single mutation. However, the effect of the, S96P mutation alone is to decrease the catalytic efficiency of the enzyme., The crystal structures of the S96P double mutants show that this bulky, proline side chain alters the water structure within the active-site, cavity (E165D; ref 1) and prevents nonproductive binding conformations of, the substrate (H95N; ref 2). Comparison of the S96P single mutant, structure with those of the wild-type cTIM, those of the single mutants, (E165D and H95N), and those of the double mutants (E165D/S96P and, H95N/S96P) begins to address the role of the conserved serine residue at, this position. The results indicate that the residue positions the, catalytic base E165 optimally for polarization of the substrate carbonyl, thereby aiding in proton abstraction. In addition, this residue is, involved in positioning critical water molecules, thereby affecting the, way in which water structure influences activity.
+The structural basis for the effect of the S96P mutation in chicken triosephosphate isomerase (cTIM) has been analyzed using a combination of X-ray crystallography and Fourier transform infrared spectroscopy. The X-ray structure is that of the enzyme complexed with phosphoglycolohydroxamate (PGH), an intermediate analogue, solved at a resolution of 1.9 A. The S96P mutation was identified as a second-site reverent when catalytically crippled mutants, E165D and H95N, were subjected to random mutagenesis. The presence of the second mutation leads to enhanced activity over the single mutation. However, the effect of the S96P mutation alone is to decrease the catalytic efficiency of the enzyme. The crystal structures of the S96P double mutants show that this bulky proline side chain alters the water structure within the active-site cavity (E165D; ref 1) and prevents nonproductive binding conformations of the substrate (H95N; ref 2). Comparison of the S96P single mutant structure with those of the wild-type cTIM, those of the single mutants (E165D and H95N), and those of the double mutants (E165D/S96P and H95N/S96P) begins to address the role of the conserved serine residue at this position. The results indicate that the residue positions the catalytic base E165 optimally for polarization of the substrate carbonyl, thereby aiding in proton abstraction. In addition, this residue is involved in positioning critical water molecules, thereby affecting the way in which water structure influences activity.
 ==About this Structure==
-TPW is a [http://en.wikipedia.org/wiki/Single_protein Single protein] structure of sequence from [http://en.wikipedia.org/wiki/Gallus_gallus Gallus gallus] with PGH as [http://en.wikipedia.org/wiki/ligand ligand]. Active as [http://en.wikipedia.org/wiki/Triose-phosphate_isomerase Triose-phosphate isomerase], with EC number [http://www.brenda-enzymes.info/php/result_flat.php4?ecno=5.3.1.1 5.3.1.1] Full crystallographic information is available from [http://ispc.weizmann.ac.il/oca-bin/ocashort?id=1TPW OCA].
+TPW is a [http://en.wikipedia.org/wiki/Single_protein Single protein] structure of sequence from [http://en.wikipedia.org/wiki/Gallus_gallus Gallus gallus] with <scene name='pdbligand=PGH:'>PGH</scene> as [http://en.wikipedia.org/wiki/ligand ligand]. Active as [http://en.wikipedia.org/wiki/Triose-phosphate_isomerase Triose-phosphate isomerase], with EC number [http://www.brenda-enzymes.info/php/result_flat.php4?ecno=5.3.1.1 5.3.1.1] Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=1TPW OCA].
 ==Reference==
@@ Line 14: / Line 14: @@
 [[Category: Single protein]]
 [[Category: Triose-phosphate isomerase]]
-[[Category: Knowles, J.R.]]
+[[Category: Knowles, J R.]]
-[[Category: Komives, E.A.]]
+[[Category: Komives, E A.]]
-[[Category: Liu, K.D.]]
+[[Category: Liu, K D.]]
 [[Category: Narayana, N.]]
-[[Category: Petsko, G.A.]]
+[[Category: Petsko, G A.]]
 [[Category: Ringe, D.]]
-[[Category: Stock, A.M.]]
+[[Category: Stock, A M.]]
 [[Category: Sugio, S.]]
-[[Category: Xuong, Ng.H.]]
+[[Category: Xuong, Ng H.]]
 [[Category: Zhang, Z.]]
 [[Category: PGH]]
 [[Category: isomerase(intramolecular oxidoreductase)]]
-''Page seeded by [http://ispc.weizmann.ac.il/oca OCA ] on Wed Nov 21 03:29:55 2007''
+''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Thu Feb 21 15:16:08 2008''