4p61: Difference between revisions
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The | ==CHICKEN TRIOSEPHOSPHATE ISOMERASE WITH LOOP6 MUTATIONS, V167P AND W168E.== | ||
<StructureSection load='4p61' size='340' side='right'caption='[[4p61]], [[Resolution|resolution]] 1.34Å' scene=''> | |||
== Structural highlights == | |||
<table><tr><td colspan='2'>[[4p61]] is a 2 chain structure with sequence from [https://en.wikipedia.org/wiki/Gallus_gallus Gallus gallus]. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=4P61 OCA]. For a <b>guided tour on the structure components</b> use [https://proteopedia.org/fgij/fg.htm?mol=4P61 FirstGlance]. <br> | |||
</td></tr><tr id='method'><td class="sblockLbl"><b>[[Empirical_models|Method:]]</b></td><td class="sblockDat" id="methodDat">X-ray diffraction, [[Resolution|Resolution]] 1.34Å</td></tr> | |||
<tr id='resources'><td class="sblockLbl"><b>Resources:</b></td><td class="sblockDat"><span class='plainlinks'>[https://proteopedia.org/fgij/fg.htm?mol=4p61 FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=4p61 OCA], [https://pdbe.org/4p61 PDBe], [https://www.rcsb.org/pdb/explore.do?structureId=4p61 RCSB], [https://www.ebi.ac.uk/pdbsum/4p61 PDBsum], [https://prosat.h-its.org/prosat/prosatexe?pdbcode=4p61 ProSAT]</span></td></tr> | |||
</table> | |||
== Function == | |||
[https://www.uniprot.org/uniprot/TPIS_CHICK TPIS_CHICK] | |||
<div style="background-color:#fffaf0;"> | |||
== Publication Abstract from PubMed == | |||
Two mutations of the phosphodianion gripper loop in chicken muscle triosephosphate isomerase (cTIM) were examined: (1) the loop deletion mutant (LDM) formed by removal of residues 170-173 [Pompliano, D. L., et al. (1990) Biochemistry 29, 3186-3194] and (2) the loop 6 replacement mutant (L6RM), in which the N-terminal hinge sequence of TIM from eukaryotes, 166-PXW-168 (X = L or V), is replaced by the sequence from archaea, 166-PPE-168. The X-ray crystal structure of the L6RM shows a large displacement of the side chain of E168 from that for W168 in wild-type cTIM. Solution nuclear magnetic resonance data show that the L6RM results in significant chemical shift changes in loop 6 and surrounding regions, and that the binding of glycerol 3-phosphate (G3P) results in chemical shift changes for nuclei at the active site of the L6RM that are smaller than those of wild-type cTIM. Interactions with loop 6 of the L6RM stabilize the enediolate intermediate toward the elimination reaction catalyzed by the LDM. The LDM and L6RM result in 800000- and 23000-fold decreases, respectively, in kcat/Km for isomerization of GAP. Saturation of the LDM, but not the L6RM, by substrate and inhibitor phosphoglycolate is detected by steady-state kinetic analyses. We propose, on the basis of a comparison of X-ray crystal structures for wild-type TIM and the L6RM, that ligands bind weakly to the L6RM because a large fraction of the ligand binding energy is utilized to overcome destabilizing electrostatic interactions between the side chains of E168 and E129 that are predicted to develop in the loop-closed enzyme. Similar normalized yields of DHAP, d-DHAP, and d-GAP are formed in LDM- and L6RM-catalyzed reactions of GAP in D2O. The smaller normalized 12-13% yield of DHAP and d-DHAP observed for the mutant cTIM-catalyzed reactions compared with the 79% yield of these products for wild-type cTIM suggests that these mutations impair the transfer of a proton from O-2 to O-1 at the initial enediolate phosphate intermediate. No products are detected for the LDM-catalyzed isomerization reactions in D2O of [1-(13)C]GA and HPi, but the L6RM-catalyzed reaction in the presence of 0.020 M dianion gives a 2% yield of the isomerization product [2-(13)C,2-(2)H]GA. | |||
Enzyme architecture: the effect of replacement and deletion mutations of loop 6 on catalysis by triosephosphate isomerase.,Zhai X, Go MK, O'Donoghue AC, Amyes TL, Pegan SD, Wang Y, Loria JP, Mesecar AD, Richard JP Biochemistry. 2014 Jun 3;53(21):3486-501. doi: 10.1021/bi500458t. Epub 2014 May, 22. PMID:24825099<ref>PMID:24825099</ref> | |||
From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.<br> | |||
</div> | |||
<div class="pdbe-citations 4p61" style="background-color:#fffaf0;"></div> | |||
==See Also== | |||
*[[Triose phosphate isomerase 3D structures|Triose phosphate isomerase 3D structures]] | |||
== References == | |||
<references/> | |||
__TOC__ | |||
</StructureSection> | |||
[[Category: Gallus gallus]] | |||
[[Category: Large Structures]] | |||
[[Category: Mesecar AD]] | |||
[[Category: Pegan SD]] | |||
