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6gaz

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Unique features of mammalian mitochondrial translation initiation revealed by cryo-EM. This file contains the 28S ribosomal subunit.

6gaz, resolution 3.10Å

Structural highlights

6gaz is a 36 chain structure with sequence from Human and Sus scrofa. Full crystallographic information is available from OCA. For a guided tour on the structure components use FirstGlance.
Ligands:
Gene:	MTIF2 (HUMAN)
Experimental data:	Check to display Experimental Data
Resources:	FirstGlance, OCA, PDBe, RCSB, PDBsum, ProSAT

Function

[IF2M_HUMAN] One of the essential components for the initiation of protein synthesis. Protects formylmethionyl-tRNA from spontaneous hydrolysis and promotes its binding to the 30S ribosomal subunits. Also involved in the hydrolysis of GTP during the formation of the 70S ribosomal complex.

Publication Abstract from PubMed

Mitochondria maintain their own specialized protein synthesis machinery, which in mammals is used exclusively for the synthesis of the membrane proteins responsible for oxidative phosphorylation(1,2). The initiation of protein synthesis in mitochondria differs substantially from bacterial or cytosolic translation systems. Mitochondrial translation initiation lacks initiation factor 1, which is essential in all other translation systems from bacteria to mammals(3,4). Furthermore, only one type of methionyl transfer RNA (tRNA(Met)) is used for both initiation and elongation(4,5), necessitating that the initiation factor specifically recognizes the formylated version of tRNA(Met) (fMet-tRNA(Met)). Lastly, most mitochondrial mRNAs do not possess 5' leader sequences to promote mRNA binding to the ribosome(2). There is currently little mechanistic insight into mammalian mitochondrial translation initiation, and it is not clear how mRNA engagement, initiator-tRNA recruitment and start-codon selection occur. Here we determine the cryo-EM structure of the complete translation initiation complex from mammalian mitochondria at 3.2 A. We describe the function of an additional domain insertion that is present in the mammalian mitochondrial initiation factor 2 (mtIF2). By closing the decoding centre, this insertion stabilizes the binding of leaderless mRNAs and induces conformational changes in the rRNA nucleotides involved in decoding. We identify unique features of mtIF2 that are required for specific recognition of fMet-tRNA(Met) and regulation of its GTPase activity. Finally, we observe that the ribosomal tunnel in the initiating ribosome is blocked by insertion of the N-terminal portion of mitochondrial protein mL45, which becomes exposed as the ribosome switches to elongation mode and may have an additional role in targeting of mitochondrial ribosomes to the protein-conducting pore in the inner mitochondrial membrane.

Unique features of mammalian mitochondrial translation initiation revealed by cryo-EM.,Kummer E, Leibundgut M, Rackham O, Lee RG, Boehringer D, Filipovska A, Ban N Nature. 2018 Aug;560(7717):263-267. doi: 10.1038/s41586-018-0373-y. Epub 2018 Aug, 8. PMID:30089917^[1]

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.

References

↑ Kummer E, Leibundgut M, Rackham O, Lee RG, Boehringer D, Filipovska A, Ban N. Unique features of mammalian mitochondrial translation initiation revealed by cryo-EM. Nature. 2018 Aug;560(7717):263-267. doi: 10.1038/s41586-018-0373-y. Epub 2018 Aug, 8. PMID:30089917 doi:http://dx.doi.org/10.1038/s41586-018-0373-y

1 Structural highlights
2 Function
3 Publication Abstract from PubMed
4 See Also
5 References

Proteopedia Page Contributors and Editors (what is this?)

OCA

Retrieved from "http://52.214.119.220/wiki/index.php/6gaz"

@@ Line 3: / Line 3: @@
 <SX load='6gaz' size='340' side='right' viewer='molstar' caption='[[6gaz]], [[Resolution|resolution]] 3.10&Aring;' scene=''>
 == Structural highlights ==
-<table><tr><td colspan='2'>[[6gaz]] is a 36 chain structure with sequence from [http://en.wikipedia.org/wiki/Human Human] and [http://en.wikipedia.org/wiki/Sus_scrofa Sus scrofa]. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=6GAZ OCA]. For a <b>guided tour on the structure components</b> use [http://oca.weizmann.ac.il/oca-docs/fgij/fg.htm?mol=6GAZ FirstGlance]. <br>
+<table><tr><td colspan='2'>[[6gaz]] is a 36 chain structure with sequence from [http://en.wikipedia.org/wiki/Human Human] and [http://en.wikipedia.org/wiki/Sus_scrofa Sus scrofa]. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=6GAZ OCA]. For a <b>guided tour on the structure components</b> use [http://proteopedia.org/fgij/fg.htm?mol=6GAZ FirstGlance]. <br>
-</td></tr><tr id='ligand'><td class="sblockLbl"><b>[[Ligand|Ligands:]]</b></td><td class="sblockDat"><scene name='pdbligand=FME:N-FORMYLMETHIONINE'>FME</scene>, <scene name='pdbligand=GSP:5-GUANOSINE-DIPHOSPHATE-MONOTHIOPHOSPHATE'>GSP</scene>, <scene name='pdbligand=GTP:GUANOSINE-5-TRIPHOSPHATE'>GTP</scene>, <scene name='pdbligand=MG:MAGNESIUM+ION'>MG</scene>, <scene name='pdbligand=NA:SODIUM+ION'>NA</scene>, <scene name='pdbligand=SPM:SPERMINE'>SPM</scene>, <scene name='pdbligand=ZN:ZINC+ION'>ZN</scene></td></tr>
+</td></tr><tr id='ligand'><td class="sblockLbl"><b>[[Ligand|Ligands:]]</b></td><td class="sblockDat" id="ligandDat"><scene name='pdbligand=FME:N-FORMYLMETHIONINE'>FME</scene>, <scene name='pdbligand=GSP:5-GUANOSINE-DIPHOSPHATE-MONOTHIOPHOSPHATE'>GSP</scene>, <scene name='pdbligand=GTP:GUANOSINE-5-TRIPHOSPHATE'>GTP</scene>, <scene name='pdbligand=MG:MAGNESIUM+ION'>MG</scene>, <scene name='pdbligand=NA:SODIUM+ION'>NA</scene>, <scene name='pdbligand=SPM:SPERMINE'>SPM</scene>, <scene name='pdbligand=ZN:ZINC+ION'>ZN</scene></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>
 <tr id='gene'><td class="sblockLbl"><b>[[Gene|Gene:]]</b></td><td class="sblockDat">MTIF2 ([http://www.ncbi.nlm.nih.gov/Taxonomy/Browser/wwwtax.cgi?mode=Info&srchmode=5&id=9606 HUMAN])</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=6gaz FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=6gaz OCA], [http://pdbe.org/6gaz PDBe], [http://www.rcsb.org/pdb/explore.do?structureId=6gaz RCSB], [http://www.ebi.ac.uk/pdbsum/6gaz PDBsum], [http://prosat.h-its.org/prosat/prosatexe?pdbcode=6gaz ProSAT]</span></td></tr>
+<tr id='resources'><td class="sblockLbl"><b>Resources:</b></td><td class="sblockDat"><span class='plainlinks'>[http://proteopedia.org/fgij/fg.htm?mol=6gaz FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=6gaz OCA], [http://pdbe.org/6gaz PDBe], [http://www.rcsb.org/pdb/explore.do?structureId=6gaz RCSB], [http://www.ebi.ac.uk/pdbsum/6gaz PDBsum], [http://prosat.h-its.org/prosat/prosatexe?pdbcode=6gaz ProSAT]</span></td></tr>
 </table>
 == Function ==

6gaz

From Proteopedia

Current revision

Unique features of mammalian mitochondrial translation initiation revealed by cryo-EM. This file contains the 28S ribosomal subunit.

Structural highlights

Function

Publication Abstract from PubMed

See Also

References

Contents

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