View source for 6nu2


==Structural insights into unique features of the human mitochondrial ribosome recycling==
<SX load='6nu2' size='340' side='right' viewer='molstar' caption='[[6nu2]], [[Resolution|resolution]] 3.90&Aring;' scene=''>
== Structural highlights ==
<table><tr><td colspan='2'>[[6nu2]] is a 85 chain structure with sequence from [http://en.wikipedia.org/wiki/Homo_sapiens Homo sapiens]. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=6NU2 OCA]. For a <b>guided tour on the structure components</b> use [http://oca.weizmann.ac.il/oca-docs/fgij/fg.htm?mol=6NU2 FirstGlance]. <br>
</td></tr><tr id='ligand'><td class="sblockLbl"><b>[[Ligand|Ligands:]]</b></td><td class="sblockDat"><scene name='pdbligand=MG:MAGNESIUM+ION'>MG</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='activity'><td class="sblockLbl"><b>Activity:</b></td><td class="sblockDat"><span class='plainlinks'>[http://en.wikipedia.org/wiki/Aminoacyl-tRNA_hydrolase Aminoacyl-tRNA hydrolase], with EC number [http://www.brenda-enzymes.info/php/result_flat.php4?ecno=3.1.1.29 3.1.1.29] </span></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=6nu2 FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=6nu2 OCA], [http://pdbe.org/6nu2 PDBe], [http://www.rcsb.org/pdb/explore.do?structureId=6nu2 RCSB], [http://www.ebi.ac.uk/pdbsum/6nu2 PDBsum], [http://prosat.h-its.org/prosat/prosatexe?pdbcode=6nu2 ProSAT]</span></td></tr>
</table>
== Disease ==
[[http://www.uniprot.org/uniprot/RT22_HUMAN RT22_HUMAN]] Hypotonia with lactic acidemia and hyperammonemia. The disease is caused by mutations affecting the gene represented in this entry. [[http://www.uniprot.org/uniprot/RT16_HUMAN RT16_HUMAN]] Combined oxidative phosphorylation defect type 2. The disease is caused by mutations affecting the gene represented in this entry. [[http://www.uniprot.org/uniprot/RM03_HUMAN RM03_HUMAN]] Combined oxidative phosphorylation defect type 9. The disease is caused by mutations affecting the gene represented in this entry. [[http://www.uniprot.org/uniprot/RM44_HUMAN RM44_HUMAN]] Infantile hypertrophic cardiomyopathy due to MRPL44 deficiency. The disease is caused by mutations affecting the gene represented in this entry. 
== Function ==
[[http://www.uniprot.org/uniprot/RRFM_HUMAN RRFM_HUMAN]] Responsible for the release of ribosomes from messenger RNA at the termination of protein biosynthesis. May increase the efficiency of translation by recycling ribosomes from one round of translation to another (By similarity). [[http://www.uniprot.org/uniprot/RM14_HUMAN RM14_HUMAN]] Forms part of 2 intersubunit bridges in the assembled ribosome. Upon binding to MALSU1 intersubunit bridge formation is blocked, preventing ribosome formation and repressing translation (Probable).<ref>PMID:22829778</ref>  [[http://www.uniprot.org/uniprot/RM36_HUMAN RM36_HUMAN]] Component of the large subunit of the mitochondrial ribosome. [[http://www.uniprot.org/uniprot/G45IP_HUMAN G45IP_HUMAN]] Acts as a negative regulator of G1 to S cell cycle phase progression by inhibiting cyclin-dependent kinases. Inhibitory effects are additive with GADD45 proteins but occurs also in the absence of GADD45 proteins. Acts as a repressor of the orphan nuclear receptor NR4A1 by inhibiting AB domain-mediated transcriptional activity. May be involved in the hormone-mediated regulation of NR4A1 transcriptional activity. May play a role in mitochondrial protein synthesis. [[http://www.uniprot.org/uniprot/RM16_HUMAN RM16_HUMAN]] Component of the large subunit of mitochondrial ribosome. [[http://www.uniprot.org/uniprot/PTCD3_HUMAN PTCD3_HUMAN]] Mitochondrial RNA-binding protein that has a role in mitochondrial translation.<ref>PMID:19427859</ref>  [[http://www.uniprot.org/uniprot/RM18_HUMAN RM18_HUMAN]] Together with thiosulfate sulfurtransferase (TST), acts as a mitochondrial import factor for the cytosolic 5S rRNA. The precursor form shows RNA chaperone activity; is able to fold the 5S rRNA into an import-competent conformation that is recognized by rhodanese (TST). Both the cytoplasmic and mitochondrial forms are able to bind to the helix IV-loop D in the gamma domain of the 5S rRNA.<ref>PMID:21685364</ref>  [[http://www.uniprot.org/uniprot/ICT1_HUMAN ICT1_HUMAN]] Essential peptidyl-tRNA hydrolase component of the mitochondrial large ribosomal subunit. Acts as a codon-independent translation release factor that has lost all stop codon specificity and directs the termination of translation in mitochondrion, possibly in case of abortive elongation. May be involved in the hydrolysis of peptidyl-tRNAs that have been prematurely terminated and thus in the recycling of stalled mitochondrial ribosomes.<ref>PMID:20186120</ref>  [[http://www.uniprot.org/uniprot/RT29_HUMAN RT29_HUMAN]] Involved in mediating interferon-gamma-induced cell death. [[http://www.uniprot.org/uniprot/AKIP_HUMAN AKIP_HUMAN]] May act as a negative regulator of Aurora-A kinase, by down-regulation through proteasome-dependent degradation. [[http://www.uniprot.org/uniprot/RM41_HUMAN RM41_HUMAN]] Component of the mitochondrial ribosome large subunit. Also involved in apoptosis and cell cycle. Enhances p53/TP53 stability, thereby contributing to p53/TP53-induced apoptosis in response to growth-inhibitory condition. Enhances p53/TP53 translocation to the mitochondria. Has the ability to arrest the cell cycle at the G1 phase, possibly by stabilizing the CDKN1A and CDKN1B (p27Kip1) proteins.<ref>PMID:16024796</ref> <ref>PMID:16256947</ref>  [[http://www.uniprot.org/uniprot/RM44_HUMAN RM44_HUMAN]] Component of the 39S subunit of mitochondrial ribosome. May have a function in the assembly/stability of nascent mitochondrial polypeptides exiting the ribosome.<ref>PMID:23315540</ref>  
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== Publication Abstract from PubMed ==
Mammalian mitochondrial ribosomes (mitoribosomes) are responsible for synthesizing proteins that are essential for oxidative phosphorylation (ATP generation). Despite their common ancestry with bacteria, the composition and structure of the human mitoribosome and its translational factors are significantly different from those of their bacterial counterparts. The mammalian mitoribosome recycling factor (RRFmt) carries a mito-specific N terminus extension (NTE), which is necessary for the function of RRFmt Here we present a 3.9-A resolution cryo-electron microscopic (cryo-EM) structure of the human 55S mitoribosome-RRFmt complex, which reveals alpha-helix and loop structures for the NTE that makes multiple mito-specific interactions with functionally critical regions of the mitoribosome. These include ribosomal RNA segments that constitute the peptidyl transferase center (PTC) and those that connect PTC with the GTPase-associated center and with mitoribosomal proteins L16 and L27. Our structure reveals the presence of a tRNA in the pe/E position and a rotation of the small mitoribosomal subunit on RRFmt binding. In addition, we observe an interaction between the pe/E tRNA and a mito-specific protein, mL64. These findings help understand the unique features of mitoribosome recycling.

Structural insights into unique features of the human mitochondrial ribosome recycling.,Koripella RK, Sharma MR, Risteff P, Keshavan P, Agrawal RK Proc Natl Acad Sci U S A. 2019 Apr 8. pii: 1815675116. doi:, 10.1073/pnas.1815675116. PMID:30962385<ref>PMID:30962385</ref>

From MEDLINE&reg;/PubMed&reg;, a database of the U.S. National Library of Medicine.<br>
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<div class="pdbe-citations 6nu2" style="background-color:#fffaf0;"></div>

==See Also==
*[[Ribosome 3D structures|Ribosome 3D structures]]
== References ==
<references/>
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</SX>
[[Category: Aminoacyl-tRNA hydrolase]]
[[Category: Homo sapiens]]
[[Category: Large Structures]]
[[Category: Agrawal, R K]]
[[Category: Koripella, R K]]
[[Category: Sharma, M R]]
[[Category: Mitochondrial ribosome recycling factor]]
[[Category: Mtrrf]]
[[Category: Ribosome]]