View source for 9fib


==Structure of 30S-IF1-IF3-mRNA-GE81112A complex==
<StructureSection load='9fib' size='340' side='right'caption='[[9fib]], [[Resolution|resolution]] 2.30&Aring;' scene=''>
== Structural highlights ==
<table><tr><td colspan='2'>[[9fib]] is a 10 chain structure with sequence from [https://en.wikipedia.org/wiki/Escherichia_coli Escherichia coli]. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=9FIB OCA]. For a <b>guided tour on the structure components</b> use [https://proteopedia.org/fgij/fg.htm?mol=9FIB 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]] 2.3&#8491;</td></tr>
<tr id='ligand'><td class="sblockLbl"><b>[[Ligand|Ligands:]]</b></td><td class="sblockDat" id="ligandDat"><scene name='pdbligand=2MG:2N-METHYLGUANOSINE-5-MONOPHOSPHATE'>2MG</scene>, <scene name='pdbligand=4OC:4N,O2-METHYLCYTIDINE-5-MONOPHOSPHATE'>4OC</scene>, <scene name='pdbligand=5MC:5-METHYLCYTIDINE-5-MONOPHOSPHATE'>5MC</scene>, <scene name='pdbligand=A1IC4:(2~{S},3~{S})-2-[[(2~{S})-2-[[(2~{S},4~{S})-5-aminocarbonyloxy-4-oxidanyl-2-[[(2~{S},3~{R})-3-oxidanylpiperidin-2-yl]carbonylamino]pentanoyl]amino]-3-(1~{H}-imidazol-4-yl)propanoyl]amino]-3-(2-chloranyl-1~{H}-imidazol-4-yl)-3-oxidanyl-propanoic+acid'>A1IC4</scene>, <scene name='pdbligand=D2T:(3R)-3-(METHYLSULFANYL)-L-ASPARTIC+ACID'>D2T</scene>, <scene name='pdbligand=G7M:N7-METHYL-GUANOSINE-5-MONOPHOSPHATE'>G7M</scene>, <scene name='pdbligand=IAS:BETA-L-ASPARTIC+ACID'>IAS</scene>, <scene name='pdbligand=K:POTASSIUM+ION'>K</scene>, <scene name='pdbligand=MA6:6N-DIMETHYLADENOSINE-5-MONOPHOSHATE'>MA6</scene>, <scene name='pdbligand=MG:MAGNESIUM+ION'>MG</scene>, <scene name='pdbligand=PSU:PSEUDOURIDINE-5-MONOPHOSPHATE'>PSU</scene>, <scene name='pdbligand=UR3:3-METHYLURIDINE-5-MONOPHOSHATE'>UR3</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=9fib FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=9fib OCA], [https://pdbe.org/9fib PDBe], [https://www.rcsb.org/pdb/explore.do?structureId=9fib RCSB], [https://www.ebi.ac.uk/pdbsum/9fib PDBsum], [https://prosat.h-its.org/prosat/prosatexe?pdbcode=9fib ProSAT]</span></td></tr>
</table>
== Function ==
[https://www.uniprot.org/uniprot/RS4_ECOLI RS4_ECOLI] One of two assembly initiator proteins for the 30S subunit, it binds directly to 16S rRNA where it nucleates assembly of the body of the 30S subunit.<ref>PMID:2461734</ref> <ref>PMID:11447122</ref> <ref>PMID:15652481</ref>   With S5 and S12 plays an important role in translational accuracy; many suppressors of streptomycin-dependent mutants of protein S12 are found in this protein, some but not all of which decrease translational accuracy (ram, ribosomal ambiguity mutations).<ref>PMID:2461734</ref> <ref>PMID:11447122</ref> <ref>PMID:15652481</ref>   Plays a role in mRNA unwinding by the ribosome, possibly by forming part of a processivity clamp.<ref>PMID:2461734</ref> <ref>PMID:11447122</ref> <ref>PMID:15652481</ref>   Protein S4 is also a translational repressor protein, it controls the translation of the alpha-operon (which codes for S13, S11, S4, RNA polymerase alpha subunit, and L17) by binding to its mRNA.<ref>PMID:2461734</ref> <ref>PMID:11447122</ref> <ref>PMID:15652481</ref>   Also functions as a rho-dependent antiterminator of rRNA transcription, increasing the synthesis of rRNA under conditions of excess protein, allowing a more rapid return to homeostasis. Binds directly to RNA polymerase.<ref>PMID:2461734</ref> <ref>PMID:11447122</ref> <ref>PMID:15652481</ref> 
<div style="background-color:#fffaf0;">
== Publication Abstract from PubMed ==
During bacterial translation initiation, the 30S ribosomal subunit, initiation factors, and initiator tRNA define the reading frame of the mRNA. This process is inhibited by kasugamycin, edeine and GE81112, however, their mechanisms of action have not been fully elucidated. Here we present cryo-electron microscopy structures of 30S initiation intermediate complexes formed in the presence of kasugamycin, edeine and GE81112 at resolutions of 2.0-2.9 A. The structures reveal that all three antibiotics bind within the E-site of the 30S and preclude 30S initiation complex formation. While kasugamycin and edeine affect early steps of 30S pre-initiation complex formation, GE81112 stalls pre-initiation complex formation at a further step by allowing start codon recognition, but impeding IF3 departure. Collectively, our work highlights how chemically distinct compounds binding at a conserved site on the 30S can interfere with translation initiation in a unique manner.

The translation inhibitors kasugamycin, edeine and GE81112 target distinct steps during 30S initiation complex formation.,Safdari HA, Morici M, Sanchez-Castro A, Dallape A, Paternoga H, Giuliodori AM, Fabbretti A, Milon P, Wilson DN Nat Commun. 2025 Mar 12;16(1):2470. doi: 10.1038/s41467-025-57731-8. PMID:40075065<ref>PMID:40075065</ref>

From MEDLINE&reg;/PubMed&reg;, a database of the U.S. National Library of Medicine.<br>
</div>
<div class="pdbe-citations 9fib" style="background-color:#fffaf0;"></div>
== References ==
<references/>
__TOC__
</StructureSection>
[[Category: Escherichia coli]]
[[Category: Large Structures]]
[[Category: Morici M]]
[[Category: Safdari HA]]
[[Category: Wilson DN]]