1tpv: Difference between revisions

Revision as of 16:16, 21 February 2008

S96P CHANGE IS A SECOND-SITE SUPPRESSOR FOR H95N SLUGGISH MUTANT TRIOSEPHOSPHATE ISOMERASE

OverviewOverview

The structural basis for the 3000-fold decrease in catalytic efficiency of the H95N mutant chicken triosephosphate isomerase and the 60-fold regain of catalytic efficiency in the double mutant, H95N.S96P, have been analyzed. The results from a combination of X-ray crystallography and Fourier transform infrared spectroscopy experiments indicate that the predominant defect in the H95N mutant isomerase appears to be its inability to bind the substrate in a coplanar, cis conformation. The structures of each mutant isomerase were determined from X-ray crystallography of the complex of phosphoglycolohydroxamate (PGH), an intermediate analog with the isomerase, and each was solved to a resolution of 1.9 A. The PGH appeared to be in two different conformations in which the enediol-mimicking atoms, O2-N2-C1-O1, of the PGH were not coplanar. No density was observed that would correspond to the coplanar conformation. Two bands are observed for the dihydroxyacetone phosphate carbonyl in the H95N mutant FTIR spectrum, and these can be explained if the O1 of DHAP, like the O1 of PGH in the crystal structure, is in two different positions. Two ordered water molecules are located between O1 of PGH and N delta of N95. Comparison of the structure of the pseudorevertant, H95N.S96P with that for the H95N single mutant, shows that S96P mutation causes the double mutant to regain the ability to bind PGH predominantly in the coplanar, cis conformation. Electron density for a single ordered water molecule bridging the N95 amide side chain and the O2 of PGH is observed, but the density was weak, perhaps indicating that the water molecule is somewhat disordered. Whether or not a water molecule is hydrogen bonded to O2 of PGH may explain the two carbonyl stretching frequencies observed for the GAP carbonyl. Together, the crystal structures and the FTIR data allow a complete explanation of the catalytic properties of these two mutant isomerases.

About this StructureAbout this Structure

1TPV 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 structural basis for pseudoreversion of the H95N lesion by the secondary S96P mutation in triosephosphate isomerase., Komives EA, Lougheed JC, Zhang Z, Sugio S, Narayana N, Xuong NH, Petsko GA, Ringe D, Biochemistry. 1996 Dec 3;35(48):15474-84. PMID:8952501

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-[[Image:1tpv.jpg|left|200px]]<br /><applet load="1tpv" size="450" color="white" frame="true" align="right" spinBox="true"
+[[Image:1tpv.jpg|left|200px]]<br /><applet load="1tpv" size="350" color="white" frame="true" align="right" spinBox="true"
 caption="1tpv, resolution 1.9&Aring;" />
 '''S96P CHANGE IS A SECOND-SITE SUPPRESSOR FOR H95N SLUGGISH MUTANT TRIOSEPHOSPHATE ISOMERASE'''<br />
 ==Overview==
-The structural basis for the 3000-fold decrease in catalytic efficiency of, the H95N mutant chicken triosephosphate isomerase and the 60-fold regain, of catalytic efficiency in the double mutant, H95N.S96P, have been, analyzed. The results from a combination of X-ray crystallography and, Fourier transform infrared spectroscopy experiments indicate that the, predominant defect in the H95N mutant isomerase appears to be its, inability to bind the substrate in a coplanar, cis conformation. The, structures of each mutant isomerase were determined from X-ray, crystallography of the complex of phosphoglycolohydroxamate (PGH), an, intermediate analog with the isomerase, and each was solved to a, resolution of 1.9 A. The PGH appeared to be in two different conformations, in which the enediol-mimicking atoms, O2-N2-C1-O1, of the PGH were not, coplanar. No density was observed that would correspond to the coplanar, conformation. Two bands are observed for the dihydroxyacetone phosphate, carbonyl in the H95N mutant FTIR spectrum, and these can be explained if, the O1 of DHAP, like the O1 of PGH in the crystal structure, is in two, different positions. Two ordered water molecules are located between O1 of, PGH and N delta of N95. Comparison of the structure of the, pseudorevertant, H95N.S96P with that for the H95N single mutant, shows, that S96P mutation causes the double mutant to regain the ability to bind, PGH predominantly in the coplanar, cis conformation. Electron density for, a single ordered water molecule bridging the N95 amide side chain and the, O2 of PGH is observed, but the density was weak, perhaps indicating that, the water molecule is somewhat disordered. Whether or not a water molecule, is hydrogen bonded to O2 of PGH may explain the two carbonyl stretching, frequencies observed for the GAP carbonyl. Together, the crystal, structures and the FTIR data allow a complete explanation of the catalytic, properties of these two mutant isomerases.
+The structural basis for the 3000-fold decrease in catalytic efficiency of the H95N mutant chicken triosephosphate isomerase and the 60-fold regain of catalytic efficiency in the double mutant, H95N.S96P, have been analyzed. The results from a combination of X-ray crystallography and Fourier transform infrared spectroscopy experiments indicate that the predominant defect in the H95N mutant isomerase appears to be its inability to bind the substrate in a coplanar, cis conformation. The structures of each mutant isomerase were determined from X-ray crystallography of the complex of phosphoglycolohydroxamate (PGH), an intermediate analog with the isomerase, and each was solved to a resolution of 1.9 A. The PGH appeared to be in two different conformations in which the enediol-mimicking atoms, O2-N2-C1-O1, of the PGH were not coplanar. No density was observed that would correspond to the coplanar conformation. Two bands are observed for the dihydroxyacetone phosphate carbonyl in the H95N mutant FTIR spectrum, and these can be explained if the O1 of DHAP, like the O1 of PGH in the crystal structure, is in two different positions. Two ordered water molecules are located between O1 of PGH and N delta of N95. Comparison of the structure of the pseudorevertant, H95N.S96P with that for the H95N single mutant, shows that S96P mutation causes the double mutant to regain the ability to bind PGH predominantly in the coplanar, cis conformation. Electron density for a single ordered water molecule bridging the N95 amide side chain and the O2 of PGH is observed, but the density was weak, perhaps indicating that the water molecule is somewhat disordered. Whether or not a water molecule is hydrogen bonded to O2 of PGH may explain the two carbonyl stretching frequencies observed for the GAP carbonyl. Together, the crystal structures and the FTIR data allow a complete explanation of the catalytic properties of these two mutant isomerases.
 ==About this Structure==
-TPV 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=1TPV OCA].
+TPV 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=1TPV 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 03:29:50 2007''
+''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Thu Feb 21 15:16:05 2008''