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==Structure of Mycobacterium tuberculosis Ribose-5-Phosphate Isomerase, RpiB, Rv2465c, in complex with 4-phospho-D-erythronate.==
<StructureSection load='2bet' size='340' side='right'caption='[[2bet]], [[Resolution|resolution]] 2.20&Aring;' scene=''>
== Structural highlights ==
<table><tr><td colspan='2'>[[2bet]] is a 5 chain structure with sequence from [https://en.wikipedia.org/wiki/Mycobacterium_tuberculosis_H37Rv Mycobacterium tuberculosis H37Rv]. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=2BET OCA]. For a <b>guided tour on the structure components</b> use [https://proteopedia.org/fgij/fg.htm?mol=2BET 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]] 2.2&#8491;</td></tr>
<tr id='ligand'><td class="sblockLbl"><b>[[Ligand|Ligands:]]</b></td><td class="sblockDat" id="ligandDat"><scene name='pdbligand=DEZ:4-PHOSPHO-D-ERYTHRONATE'>DEZ</scene></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=2bet FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=2bet OCA], [https://pdbe.org/2bet PDBe], [https://www.rcsb.org/pdb/explore.do?structureId=2bet RCSB], [https://www.ebi.ac.uk/pdbsum/2bet PDBsum], [https://prosat.h-its.org/prosat/prosatexe?pdbcode=2bet ProSAT]</span></td></tr>
</table>
== Function ==
[https://www.uniprot.org/uniprot/RPIB_MYCTU RPIB_MYCTU] Has isomerase activity towards D-ribose 5-phosphate, but not towards D-allose 6-phosphate.
== Evolutionary Conservation ==
[[Image:Consurf_key_small.gif|200px|right]]
Check<jmol>
  <jmolCheckbox>
    <scriptWhenChecked>; select protein; define ~consurf_to_do selected; consurf_initial_scene = true; script "/wiki/ConSurf/be/2bet_consurf.spt"</scriptWhenChecked>
    <scriptWhenUnchecked>script /wiki/extensions/Proteopedia/spt/initialview01.spt</scriptWhenUnchecked>
    <text>to colour the structure by Evolutionary Conservation</text>
  </jmolCheckbox>
</jmol>, as determined by [http://consurfdb.tau.ac.il/ ConSurfDB]. You may read the [[Conservation%2C_Evolutionary|explanation]] of the method and the full data available from [http://bental.tau.ac.il/new_ConSurfDB/main_output.php?pdb_ID=2bet ConSurf].
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== Publication Abstract from PubMed ==
Ribose-5-phosphate isomerase (Rpi), an important enzyme in the pentose phosphate pathway, catalyzes the interconversion of ribulose 5-phosphate and ribose 5-phosphate. Two unrelated isomerases have been identified, RpiA and RpiB, with different structures and active site residues. The reaction catalyzed by both enzymes is thought to proceed via a high energy enediolate intermediate, by analogy to other carbohydrate isomerases. Here we present studies of RpiB from Mycobacterium tuberculosis together with small molecules designed to resemble the enediolate intermediate. The relative affinities of these inhibitors for RpiB have a different pattern than that observed previously for the RpiA from spinach. X-ray structures of RpiB in complex with the inhibitors 4-phospho-d-erythronohydroxamic acid (K(m) 57 microm) and 4-phospho-d-erythronate (K(i) 1.7 mm) refined to resolutions of 2.1 and 2.2 A, respectively, allowed us to assign roles for most active site residues. These results, combined with docking of the substrates in the position of the most effective inhibitor, now allow us to outline the reaction mechanism for RpiBs. Both enzymes have residues that can catalyze opening of the furanose ring of the ribose 5-phosphate and so can improve the efficiency of the reaction. Both enzymes also have an acidic residue that acts as a base in the isomerization step. A lysine residue in RpiAs provides for more efficient stabilization of the intermediate than the corresponding uncharged groups of RpiBs; this same feature lies behind the more efficient binding of RpiA to 4-phospho-d-erythronate.

Competitive inhibitors of Mycobacterium tuberculosis ribose-5-phosphate isomerase B reveal new information about the reaction mechanism.,Roos AK, Burgos E, Ericsson DJ, Salmon L, Mowbray SL J Biol Chem. 2005 Feb 25;280(8):6416-22. Epub 2004 Dec 7. PMID:15590681<ref>PMID:15590681</ref>

From MEDLINE&reg;/PubMed&reg;, a database of the U.S. National Library of Medicine.<br>
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==See Also==
*[[Ribose-5-phosphate isomerase 3D structures|Ribose-5-phosphate isomerase 3D structures]]
== References ==
<references/>
__TOC__
</StructureSection>
[[Category: Large Structures]]
[[Category: Mycobacterium tuberculosis H37Rv]]
[[Category: Ericsson DJ]]
[[Category: Mowbray SL]]
[[Category: Roos AK]]