3j8c: Difference between revisions

No edit summary
No edit summary
Line 4: Line 4:
== Structural highlights ==
== Structural highlights ==
<table><tr><td colspan='2'>[[3j8c]] is a 8 chain structure with sequence from [https://en.wikipedia.org/wiki/Homo_sapiens Homo sapiens]. This structure supersedes the now removed PDB entry [http://oca.weizmann.ac.il/oca-bin/send-pdb?obs=1&id=3j7k 3j7k]. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=3J8C OCA]. For a <b>guided tour on the structure components</b> use [https://proteopedia.org/fgij/fg.htm?mol=3J8C FirstGlance]. <br>
<table><tr><td colspan='2'>[[3j8c]] is a 8 chain structure with sequence from [https://en.wikipedia.org/wiki/Homo_sapiens Homo sapiens]. This structure supersedes the now removed PDB entry [http://oca.weizmann.ac.il/oca-bin/send-pdb?obs=1&id=3j7k 3j7k]. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=3J8C OCA]. For a <b>guided tour on the structure components</b> use [https://proteopedia.org/fgij/fg.htm?mol=3J8C FirstGlance]. <br>
</td></tr><tr id='NonStdRes'><td class="sblockLbl"><b>[[Non-Standard_Residue|NonStd Res:]]</b></td><td class="sblockDat"><scene name='pdbligand=UNK:UNKNOWN'>UNK</scene></td></tr>
</td></tr><tr id='method'><td class="sblockLbl"><b>[[Empirical_models|Method:]]</b></td><td class="sblockDat" id="methodDat">Electron Microscopy, [[Resolution|Resolution]] 11.6&#8491;</td></tr>
<tr id='related'><td class="sblockLbl"><b>[[Related_structure|Related:]]</b></td><td class="sblockDat"><div style='overflow: auto; max-height: 3em;'>[[3j8b|3j8b]], [[4u1d|4u1d]], [[4u1c|4u1c]], [[4lct|4lct]], [[4b4t|4b4t]], [[4o8x|4o8x]], [[1rz4|1rz4]], [[3chm|3chm]], [[3j47|3j47]]</div></td></tr>
<tr id='activity'><td class="sblockLbl"><b>Activity:</b></td><td class="sblockDat"><span class='plainlinks'>[https://en.wikipedia.org/wiki/Ubiquitinyl_hydrolase_1 Ubiquitinyl hydrolase 1], with EC number [https://www.brenda-enzymes.info/php/result_flat.php4?ecno=3.4.19.12 3.4.19.12] </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=3j8c FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=3j8c OCA], [https://pdbe.org/3j8c PDBe], [https://www.rcsb.org/pdb/explore.do?structureId=3j8c RCSB], [https://www.ebi.ac.uk/pdbsum/3j8c PDBsum], [https://prosat.h-its.org/prosat/prosatexe?pdbcode=3j8c 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=3j8c FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=3j8c OCA], [https://pdbe.org/3j8c PDBe], [https://www.rcsb.org/pdb/explore.do?structureId=3j8c RCSB], [https://www.ebi.ac.uk/pdbsum/3j8c PDBsum], [https://prosat.h-its.org/prosat/prosatexe?pdbcode=3j8c ProSAT]</span></td></tr>
</table>
</table>
== Function ==
[https://www.uniprot.org/uniprot/EIF3A_HUMAN EIF3A_HUMAN] RNA-binding component of the eukaryotic translation initiation factor 3 (eIF-3) complex, which is required for several steps in the initiation of protein synthesis (PubMed:17581632, PubMed:25849773). The eIF-3 complex associates with the 40S ribosome and facilitates the recruitment of eIF-1, eIF-1A, eIF-2:GTP:methionyl-tRNAi and eIF-5 to form the 43S pre-initiation complex (43S PIC). The eIF-3 complex stimulates mRNA recruitment to the 43S PIC and scanning of the mRNA for AUG recognition. The eIF-3 complex is also required for disassembly and recycling of post-termination ribosomal complexes and subsequently prevents premature joining of the 40S and 60S ribosomal subunits prior to initiation (PubMed:17581632, PubMed:11169732). The eIF-3 complex specifically targets and initiates translation of a subset of mRNAs involved in cell proliferation, including cell cycling, differentiation and apoptosis, and uses different modes of RNA stem-loop binding to exert either translational activation or repression (PubMed:25849773, PubMed:27462815).[HAMAP-Rule:MF_03000]<ref>PMID:11169732</ref> <ref>PMID:17581632</ref> <ref>PMID:25849773</ref> <ref>PMID:27462815</ref>  (Microbial infection) Essential for the initiation of translation on type-1 viral ribosomal entry sites (IRESs), like for HCV, PV, EV71 or BEV translation (PubMed:23766293, PubMed:24357634).<ref>PMID:23766293</ref> <ref>PMID:24357634</ref>  (Microbial infection) In case of FCV infection, plays a role in the ribosomal termination-reinitiation event leading to the translation of VP2 (PubMed:18056426).<ref>PMID:18056426</ref>
<div style="background-color:#fffaf0;">
<div style="background-color:#fffaf0;">
== Publication Abstract from PubMed ==
== Publication Abstract from PubMed ==
Eukaryotic translation initiation begins with assembly of a 43S preinitiation complex. First, methionylated initiator methionine transfer RNA (Met-tRNAi(Met)), eukaryotic initiation factor (eIF) 2, and guanosine triphosphate form a ternary complex (TC). The TC, eIF3, eIF1, and eIF1A cooperatively bind to the 40S subunit, yielding the 43S preinitiation complex, which is ready to attach to messenger RNA (mRNA) and start scanning to the initiation codon. Scanning on structured mRNAs additionally requires DHX29, a DExH-box protein that also binds directly to the 40S subunit. Here, we present a cryo-electron microscopy structure of the mammalian DHX29-bound 43S complex at 11.6 A resolution. It reveals that eIF2 interacts with the 40S subunit via its alpha subunit and supports Met-tRNAi(Met) in an unexpected P/I orientation (eP/I). The structural core of eIF3 resides on the back of the 40S subunit, establishing two principal points of contact, whereas DHX29 binds around helix 16. The structure provides insights into eukaryote-specific aspects of translation, including the mechanism of action of DHX29.
Eukaryotic translation initiation requires the recruitment of the large, multiprotein eIF3 complex to the 40S ribosomal subunit. We present X-ray structures of all major components of the minimal, six-subunit Saccharomyces cerevisiae eIF3 core. These structures, together with electron microscopy reconstructions, cross-linking coupled to mass spectrometry, and integrative structure modeling, allowed us to position and orient all eIF3 components on the 40SeIF1 complex, revealing an extended, modular arrangement of eIF3 subunits. Yeast eIF3 engages 40S in a clamp-like manner, fully encircling 40S to position key initiation factors on opposite ends of the mRNA channel, providing a platform for the recruitment, assembly, and regulation of the translation initiation machinery. The structures of eIF3 components reported here also have implications for understanding the architecture of the mammalian 43S preinitiation complex and the complex of eIF3, 40S, and the hepatitis C internal ribosomal entry site RNA.


Structure of the mammalian ribosomal 43S preinitiation complex bound to the scanning factor DHX29.,Hashem Y, des Georges A, Dhote V, Langlois R, Liao HY, Grassucci RA, Hellen CU, Pestova TV, Frank J Cell. 2013 May 23;153(5):1108-19. doi: 10.1016/j.cell.2013.04.036. PMID:23706745<ref>PMID:23706745</ref>
Molecular Architecture of the 40SeIF1eIF3 Translation Initiation Complex.,Erzberger JP, Stengel F, Pellarin R, Zhang S, Schaefer T, Aylett CH, Cimermancic P, Boehringer D, Sali A, Aebersold R, Ban N Cell. 2014 Aug 28;158(5):1123-35. doi: 10.1016/j.cell.2014.07.044. PMID:25171412<ref>PMID:25171412</ref>


From MEDLINE&reg;/PubMed&reg;, a database of the U.S. National Library of Medicine.<br>
From MEDLINE&reg;/PubMed&reg;, a database of the U.S. National Library of Medicine.<br>
Line 27: Line 27:
[[Category: Homo sapiens]]
[[Category: Homo sapiens]]
[[Category: Large Structures]]
[[Category: Large Structures]]
[[Category: Ubiquitinyl hydrolase 1]]
[[Category: Ban N]]
[[Category: Ban, N]]
[[Category: Erzberger JP]]
[[Category: Erzberger, J P]]
[[Category: Translation]]

Proteopedia Page Contributors and Editors (what is this?)Proteopedia Page Contributors and Editors (what is this?)

OCA