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| | <StructureSection load='5uay' size='340' side='right'caption='[[5uay]], [[Resolution|resolution]] 2.50Å' scene=''> | | <StructureSection load='5uay' size='340' side='right'caption='[[5uay]], [[Resolution|resolution]] 2.50Å' scene=''> |
| | == Structural highlights == | | == Structural highlights == |
| - | <table><tr><td colspan='2'>[[5uay]] is a 1 chain structure with sequence from [http://en.wikipedia.org/wiki/Arath Arath]. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=5UAY OCA]. For a <b>guided tour on the structure components</b> use [http://oca.weizmann.ac.il/oca-docs/fgij/fg.htm?mol=5UAY FirstGlance]. <br> | + | <table><tr><td colspan='2'>[[5uay]] is a 1 chain structure with sequence from [https://en.wikipedia.org/wiki/Arabidopsis_thaliana Arabidopsis thaliana]. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=5UAY OCA]. For a <b>guided tour on the structure components</b> use [https://proteopedia.org/fgij/fg.htm?mol=5UAY FirstGlance]. <br> |
| - | </td></tr><tr id='NonStdRes'><td class="sblockLbl"><b>[[Non-Standard_Residue|NonStd Res:]]</b></td><td class="sblockDat"><scene name='pdbligand=MSE:SELENOMETHIONINE'>MSE</scene></td></tr> | + | </td></tr><tr id='method'><td class="sblockLbl"><b>[[Empirical_models|Method:]]</b></td><td class="sblockDat" id="methodDat">X-ray diffraction, [[Resolution|Resolution]] 2.5Å</td></tr> |
| - | <tr id='gene'><td class="sblockLbl"><b>[[Gene|Gene:]]</b></td><td class="sblockDat">TOC75-3, TOC75, At3g46740, T6H20.230 ([http://www.ncbi.nlm.nih.gov/Taxonomy/Browser/wwwtax.cgi?mode=Info&srchmode=5&id=3702 ARATH])</td></tr> | + | <tr id='ligand'><td class="sblockLbl"><b>[[Ligand|Ligands:]]</b></td><td class="sblockDat" id="ligandDat"><scene name='pdbligand=MSE:SELENOMETHIONINE'>MSE</scene></td></tr> |
| - | <tr id='resources'><td class="sblockLbl"><b>Resources:</b></td><td class="sblockDat"><span class='plainlinks'>[http://oca.weizmann.ac.il/oca-docs/fgij/fg.htm?mol=5uay FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=5uay OCA], [http://pdbe.org/5uay PDBe], [http://www.rcsb.org/pdb/explore.do?structureId=5uay RCSB], [http://www.ebi.ac.uk/pdbsum/5uay PDBsum], [http://prosat.h-its.org/prosat/prosatexe?pdbcode=5uay ProSAT]</span></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=5uay FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=5uay OCA], [https://pdbe.org/5uay PDBe], [https://www.rcsb.org/pdb/explore.do?structureId=5uay RCSB], [https://www.ebi.ac.uk/pdbsum/5uay PDBsum], [https://prosat.h-its.org/prosat/prosatexe?pdbcode=5uay ProSAT]</span></td></tr> |
| | </table> | | </table> |
| | == Function == | | == Function == |
| - | [[http://www.uniprot.org/uniprot/TC753_ARATH TC753_ARATH]] Essential protein. Mediates the insertion of proteins targeted to the outer membrane of chloroplasts (By similarity). Required for the import of protein precursors into chloroplasts. Forms the voltage-dependent preprotein translocation channels (hydrophilic beta barrel) of the TOC complex in the chloroplastic outer membrane.<ref>PMID:15908591</ref> | + | [https://www.uniprot.org/uniprot/TC753_ARATH TC753_ARATH] Essential protein. Mediates the insertion of proteins targeted to the outer membrane of chloroplasts (By similarity). Required for the import of protein precursors into chloroplasts. Forms the voltage-dependent preprotein translocation channels (hydrophilic beta barrel) of the TOC complex in the chloroplastic outer membrane.<ref>PMID:15908591</ref> |
| | <div style="background-color:#fffaf0;"> | | <div style="background-color:#fffaf0;"> |
| | == Publication Abstract from PubMed == | | == Publication Abstract from PubMed == |
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| | __TOC__ | | __TOC__ |
| | </StructureSection> | | </StructureSection> |
| - | [[Category: Arath]] | + | [[Category: Arabidopsis thaliana]] |
| | [[Category: Large Structures]] | | [[Category: Large Structures]] |
| - | [[Category: Neil, P K.O]]
| + | [[Category: Noinaj N]] |
| - | [[Category: Noinaj, N]] | + | [[Category: O'Neil PK]] |
| - | [[Category: Chloroplast]] | + | |
| - | [[Category: Membrane protein]]
| + | |
| - | [[Category: Potra]]
| + | |
| Structural highlights
Function
TC753_ARATH Essential protein. Mediates the insertion of proteins targeted to the outer membrane of chloroplasts (By similarity). Required for the import of protein precursors into chloroplasts. Forms the voltage-dependent preprotein translocation channels (hydrophilic beta barrel) of the TOC complex in the chloroplastic outer membrane.[1]
Publication Abstract from PubMed
Protein trafficking across membranes is an essential function in cells; however, the exact mechanism for how this occurs is not well understood. In the endosymbionts, mitochondria and chloroplasts, the vast majority of proteins are synthesized in the cytoplasm as preproteins and then imported into the organelles via specialized machineries. In chloroplasts, protein import is accomplished by the TOC (translocon on the outer chloroplast membrane) and TIC (translocon on the inner chloroplast membrane) machineries in the outer and inner envelope membranes, respectively. TOC mediates initial recognition of preproteins at the outer membrane and includes a core membrane channel, Toc75, and two receptor proteins, Toc33/34 and Toc159, each containing GTPase domains that control preprotein binding and translocation. Toc75 is predicted to have a beta-barrel fold consisting of an N-terminal intermembrane space (IMS) domain and a C-terminal 16-stranded beta-barrel domain. Here we report the crystal structure of the N-terminal IMS domain of Toc75 from Arabidopsis thaliana, revealing three tandem polypeptide transport-associated (POTRA) domains, with POTRA2 containing an additional elongated helix not observed previously in other POTRA domains. Functional studies show an interaction with the preprotein, preSSU, which is mediated through POTRA2-3. POTRA2-3 also was found to have chaperone-like activity in an insulin aggregation assay, which we propose facilitates preprotein import. Our data suggest a model in which the POTRA domains serve as a binding site for the preprotein as it emerges from the Toc75 channel and provide a chaperone-like activity to prevent misfolding or aggregation as the preprotein traverses the intermembrane space.
The POTRA domains of Toc75 exhibit chaperone-like function to facilitate import into chloroplasts.,O'Neil PK, Richardson LGL, Paila YD, Piszczek G, Chakravarthy S, Noinaj N, Schnell D Proc Natl Acad Sci U S A. 2017 Jun 13;114(24):E4868-E4876. doi:, 10.1073/pnas.1621179114. Epub 2017 May 30. PMID:28559331[2]
From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.
References
- ↑ Baldwin A, Wardle A, Patel R, Dudley P, Park SK, Twell D, Inoue K, Jarvis P. A molecular-genetic study of the Arabidopsis Toc75 gene family. Plant Physiol. 2005 Jun;138(2):715-33. Epub 2005 May 20. PMID:15908591 doi:http://dx.doi.org/pp.105.063289
- ↑ O'Neil PK, Richardson LGL, Paila YD, Piszczek G, Chakravarthy S, Noinaj N, Schnell D. The POTRA domains of Toc75 exhibit chaperone-like function to facilitate import into chloroplasts. Proc Natl Acad Sci U S A. 2017 Jun 13;114(24):E4868-E4876. doi:, 10.1073/pnas.1621179114. Epub 2017 May 30. PMID:28559331 doi:http://dx.doi.org/10.1073/pnas.1621179114
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