View source for 8bqx


==Yeast 80S ribosome in complex with Map1 (conformation 2)==
<StructureSection load='8bqx' size='340' side='right'caption='[[8bqx]], [[Resolution|resolution]] 3.80&Aring;' scene=''>
== Structural highlights ==
<table><tr><td colspan='2'>[[8bqx]] is a 10 chain structure with sequence from [https://en.wikipedia.org/wiki/Saccharomyces_cerevisiae Saccharomyces cerevisiae]. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=8BQX OCA]. For a <b>guided tour on the structure components</b> use [https://proteopedia.org/fgij/fg.htm?mol=8BQX FirstGlance]. <br>
</td></tr><tr id='method'><td class="sblockLbl"><b>[[Empirical_models|Method:]]</b></td><td class="sblockDat" id="methodDat">Electron Microscopy, [[Resolution|Resolution]] 3.8&#8491;</td></tr>
<tr id='ligand'><td class="sblockLbl"><b>[[Ligand|Ligands:]]</b></td><td class="sblockDat" id="ligandDat"><scene name='pdbligand=ZN:ZINC+ION'>ZN</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=8bqx FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=8bqx OCA], [https://pdbe.org/8bqx PDBe], [https://www.rcsb.org/pdb/explore.do?structureId=8bqx RCSB], [https://www.ebi.ac.uk/pdbsum/8bqx PDBsum], [https://prosat.h-its.org/prosat/prosatexe?pdbcode=8bqx ProSAT]</span></td></tr>
</table>
== Function ==
[https://www.uniprot.org/uniprot/MAP1_YEAST MAP1_YEAST] Cotranslationally removes the N-terminal methionine from nascent proteins. The N-terminal methionine is often cleaved when the second residue in the primary sequence is small and uncharged (Met-Ala-, Cys, Gly, Pro, Ser, Thr, or Val). Plays the major role in N-terminal methionine removal. Less efficient when the second residue is Val.<ref>PMID:11811952</ref> <ref>PMID:11968008</ref> <ref>PMID:12874831</ref> <ref>PMID:35584675</ref> <ref>PMID:7862096</ref> 
<div style="background-color:#fffaf0;">
== Publication Abstract from PubMed ==
Cotranslational modification of the nascent polypeptide chain is one of the first events during the birth of a new protein. In eukaryotes, methionine aminopeptidases (MetAPs) cleave off the starter methionine, whereas N-acetyl-transferases (NATs) catalyze N-terminal acetylation. MetAPs and NATs compete with other cotranslationally acting chaperones, such as ribosome-associated complex (RAC), protein targeting and translocation factors (SRP and Sec61) for binding sites at the ribosomal tunnel exit. Yet, whereas well-resolved structures for ribosome-bound RAC, SRP and Sec61, are available, structural information on the mode of ribosome interaction of eukaryotic MetAPs or of the five cotranslationally active NATs is only available for NatA. Here, we present cryo-EM structures of yeast Map1 and NatB bound to ribosome-nascent chain complexes. Map1 is mainly associated with the dynamic rRNA expansion segment ES27a, thereby kept at an ideal position below the tunnel exit to act on the emerging substrate nascent chain. For NatB, we observe two copies of the NatB complex. NatB-1 binds directly below the tunnel exit, again involving ES27a, and NatB-2 is located below the second universal adapter site (eL31 and uL22). The binding mode of the two NatB complexes on the ribosome differs but overlaps with that of NatA and Map1, implying that NatB binds exclusively to the tunnel exit. We further observe that ES27a adopts distinct conformations when bound to NatA, NatB, or Map1, together suggesting a contribution to the coordination of a sequential activity of these factors on the emerging nascent chain at the ribosomal exit tunnel.

The dynamic architecture of Map1- and NatB-ribosome complexes coordinates the sequential modifications of nascent polypeptide chains.,Knorr AG, Mackens-Kiani T, Musial J, Berninghausen O, Becker T, Beatrix B, Beckmann R PLoS Biol. 2023 Apr 20;21(4):e3001995. doi: 10.1371/journal.pbio.3001995. , eCollection 2023 Apr. PMID:37079644<ref>PMID:37079644</ref>

From MEDLINE&reg;/PubMed&reg;, a database of the U.S. National Library of Medicine.<br>
</div>
<div class="pdbe-citations 8bqx" style="background-color:#fffaf0;"></div>

==See Also==
*[[Ribosome 3D structures|Ribosome 3D structures]]
== References ==
<references/>
__TOC__
</StructureSection>
[[Category: Large Structures]]
[[Category: Saccharomyces cerevisiae]]
[[Category: Beatrix B]]
[[Category: Becker T]]
[[Category: Beckmann R]]
[[Category: Berninghausen O]]
[[Category: Knorr AG]]
[[Category: Mackens-Kiani T]]
[[Category: Musial J]]