1rm3: Difference between revisions

<StructureSection load='1rm3' size='340' side='right'caption='[[1rm3]], [[Resolution|resolution]] 2.20&Aring;' scene=''>

== Structural highlights ==

<table><tr><td colspan='2'>[[1rm3]] is a 3 chain structure with sequence from [https://en.wikipedia.org/wiki/Spinacia_oleracea Spinacia oleracea]. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=1RM3 OCA]. For a <b>guided tour on the structure components</b> use [https://proteopedia.org/fgij/fg.htm?mol=1RM3 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=NDP:NADPH+DIHYDRO-NICOTINAMIDE-ADENINE-DINUCLEOTIDE+PHOSPHATE'>NDP</scene>, <scene name='pdbligand=SO4:SULFATE+ION'>SO4</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=1rm3 FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=1rm3 OCA], [https://pdbe.org/1rm3 PDBe], [https://www.rcsb.org/pdb/explore.do?structureId=1rm3 RCSB], [https://www.ebi.ac.uk/pdbsum/1rm3 PDBsum], [https://prosat.h-its.org/prosat/prosatexe?pdbcode=1rm3 ProSAT]</span></td></tr>

</table>

== Function ==

[https://www.uniprot.org/uniprot/G3PA_SPIOL G3PA_SPIOL]

== Evolutionary Conservation ==

[[Image:Consurf_key_small.gif|200px|right]]

    <scriptWhenChecked>; select protein; define ~consurf_to_do selected; consurf_initial_scene = true; script "/wiki/ConSurf/rm/1rm3_consurf.spt"</scriptWhenChecked>

  </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=1rm3 ConSurf].

<div style="clear:both"></div>

Chloroplast glyceraldehyde-3-phosphate dehydrogenase (GAPDH) of higher plants uses both NADP(H) and NAD(H) as coenzyme and consists of one (GapA) or two types of subunits (GapA, GapB). AB-GAPDH is regulated in vivo through the action of thioredoxin and metabolites, showing higher kinetic preference for NADPH in the light than in darkness due to a specific effect on kcat(NADPH). Previous crystallographic studies on spinach chloroplast A4-GAPDH complexed with NADP or NAD showed that residues Thr33 and Ser188 are involved in NADP over NAD selectivity by interacting with the 2'-phosphate group of NADP. This suggested a possible involvement of these residues in the regulatory mechanism. Mutants of recombinant spinach GapA (A4-GAPDH) with Thr33 or Ser188 replaced by Ala (T33A, S188A and double mutant T33A/S188A) were produced, expressed in Escherichia coli, and compared to wild-type recombinant A4-GAPDH, in terms of crystal structures and kinetic properties. Affinity for NADPH was decreased significantly in all mutants, and kcat(NADPH) was lowered in mutants carrying the substitution of Ser188. NADH-dependent activity was unaffected. The decrease of kcat/Km of the NADPH-dependent reaction in Ser188 mutants resembles the behaviour of AB-GAPDH inhibited by oxidized thioredoxin, as confirmed by steady-state kinetic analysis of native enzyme. A significant expansion of size of the A4-tetramer was observed in the S188A mutant compared to wild-type A4. We conclude that in the absence of interactions between Ser188 and the 2'-phosphate group of NADP, the enzyme structure relaxes to a less compact conformation, which negatively affects the complex catalytic cycle of GADPH. A model based on this concept might be developed to explain the in vivo light-regulation of the GAPDH.

Coenzyme site-directed mutants of photosynthetic A4-GAPDH show selectively reduced NADPH-dependent catalysis, similar to regulatory AB-GAPDH inhibited by oxidized thioredoxin.,Sparla F, Fermani S, Falini G, Zaffagnini M, Ripamonti A, Sabatino P, Pupillo P, Trost P J Mol Biol. 2004 Jul 23;340(5):1025-37. PMID:15236965<ref>PMID:15236965</ref>

==See Also==

*[[Glyceraldehyde-3-phosphate dehydrogenase 3D structures|Glyceraldehyde-3-phosphate dehydrogenase 3D structures]]

== References ==

<references/>

</StructureSection>

[[Category: Large Structures]]

[[Category: Falini G]]

[[Category: Fermani S]]

[[Category: Pupillo P]]

[[Category: Ripamonti A]]

[[Category: Sabatino P]]

[[Category: Sparla F]]

[[Category: Trost P]]