View source for 1jpj


==GMPPNP Complex of SRP GTPase NG Domain==
<StructureSection load='1jpj' size='340' side='right'caption='[[1jpj]], [[Resolution|resolution]] 2.30&Aring;' scene=''>
== Structural highlights ==
<table><tr><td colspan='2'>[[1jpj]] is a 1 chain structure with sequence from [https://en.wikipedia.org/wiki/Thermus_aquaticus Thermus aquaticus]. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=1JPJ OCA]. For a <b>guided tour on the structure components</b> use [https://proteopedia.org/fgij/fg.htm?mol=1JPJ 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]] 2.3&#8491;</td></tr>
<tr id='ligand'><td class="sblockLbl"><b>[[Ligand|Ligands:]]</b></td><td class="sblockDat" id="ligandDat"><scene name='pdbligand=GNP:PHOSPHOAMINOPHOSPHONIC+ACID-GUANYLATE+ESTER'>GNP</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=1jpj FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=1jpj OCA], [https://pdbe.org/1jpj PDBe], [https://www.rcsb.org/pdb/explore.do?structureId=1jpj RCSB], [https://www.ebi.ac.uk/pdbsum/1jpj PDBsum], [https://prosat.h-its.org/prosat/prosatexe?pdbcode=1jpj ProSAT]</span></td></tr>
</table>
== Function ==
[https://www.uniprot.org/uniprot/SRP54_THEAQ SRP54_THEAQ] Involved in targeting and insertion of nascent membrane proteins into the cytoplasmic membrane. Binds to the hydrophobic signal sequence of the ribosome-nascent chain (RNC) as it emerges from the ribosomes. The SRP-RNC complex is then targeted to the cytoplasmic membrane where it interacts with the SRP receptor FtsY (By similarity).[HAMAP-Rule:MF_00306]
== 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/jp/1jpj_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=1jpj ConSurf].
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== Publication Abstract from PubMed ==
BACKGROUND: The signal recognition particle (SRP) is a phylogenetically conserved ribonucleoprotein that mediates cotranslational targeting of secreted and membrane proteins to the membrane. Targeting is regulated by GTP binding and hydrolysis events that require direct interaction between structurally homologous "NG" GTPase domains of the SRP signal recognition subunit and its membrane-associated receptor, SR alpha. Structures of both the apo and GDP bound NG domains of the prokaryotic SRP54 homolog, Ffh, and the prokaryotic receptor homolog, FtsY, have been determined. The structural basis for the GTP-dependent interaction between the two proteins, however, remains unknown. RESULTS: We report here two structures of the NG GTPase of Ffh from Thermus aquaticus bound to the nonhydrolyzable GTP analog GMPPNP. Both structures reveal an unexpected binding mode in which the beta-phosphate is kinked away from the binding site and magnesium is not bound. Binding of the GTP analog in the canonical conformation found in other GTPase structures is precluded by constriction of the phosphate binding P loop. The structural difference between the Ffh complex and other GTPases suggests a specific conformational change that must accompany movement of the nucleotide from an "inactive" to an "active" binding mode. CONCLUSIONS: Conserved side chains of the GTPase sequence motifs unique to the SRP subfamily may function to gate formation of the active GTP bound conformation. Exposed hydrophobic residues provide an interaction surface that may allow regulation of the GTP binding conformation, and thus activation of the GTPase, during the association of SRP with its receptor.

The conformation of bound GMPPNP suggests a mechanism for gating the active site of the SRP GTPase.,Padmanabhan S, Freymann DM Structure. 2001 Sep;9(9):859-67. PMID:11566135<ref>PMID:11566135</ref>

From MEDLINE&reg;/PubMed&reg;, a database of the U.S. National Library of Medicine.<br>
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<div class="pdbe-citations 1jpj" style="background-color:#fffaf0;"></div>

==See Also==
*[[Signal recognition particle protein|Signal recognition particle protein]]
== References ==
<references/>
__TOC__
</StructureSection>
[[Category: Large Structures]]
[[Category: Thermus aquaticus]]
[[Category: Freymann DM]]
[[Category: Padmanabhan S]]