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{{Short description|Protein complex}} |
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[[File:Mitochondrion structure.svg|thumb|300px|A diagram showing [[mtDNA]] (circular) and mitochondrial ribosomes among other mitochondria structures]] |
[[File:Mitochondrion structure.svg|thumb|300px|A diagram showing [[mtDNA]] (circular) and mitochondrial ribosomes among other mitochondria structures]] |
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The '''mitochondrial ribosome''', or '''mitoribosome''', is a [[Protein complexes|protein complex]] that is active in [[mitochondria]] and functions as a [[Ribosomal protein|riboprotein]] for [[Translation (biology)|translating]] mitochondrial [[mRNA]]s encoded in [[mtDNA]]. Mitoribosomes, like [[cytoplasm]]ic [[ribosome]]s, consist of two subunits — large ( |
The '''mitochondrial ribosome''', or '''mitoribosome''', is a [[Protein complexes|protein complex]] that is active in [[mitochondria]] and functions as a [[Ribosomal protein|riboprotein]] for [[Translation (biology)|translating]] mitochondrial [[mRNA]]s encoded in [[mtDNA]]. The mitoribosome is attached to the [[inner mitochondrial membrane]].<ref name=":02" /> Mitoribosomes, like [[cytoplasm]]ic [[ribosome]]s, consist of two subunits — large (mt-LSU) and small (mt-SSU).<ref name="AmuntsBrown2015">{{cite journal | vauthors = Amunts A, Brown A, Toots J, Scheres SH, RamakrishnanV | title = Ribosome. The structure of the human mitochondrial ribosome | journal = Science | volume = 348 | issue = 6230 | pages = 95–98 | date = April 2015 | pmid = 25838379 | pmc = 4501431 | doi = 10.1126/science.aaa1193 }}</ref> Mitoribosomes consistof several specific proteins and fewer rRNAs.<ref name="AmuntsBrown2015"/> While mitochondrial rRNAs are encoded in the [[Mitochondrial DNA|mitochondrial genome]], the proteins that make up mitoribosomes are encoded in the [[Cell nucleus|nucleus]] and assembled by cytoplasmic ribosomes before being implanted into the mitochondria.<ref name=":3">{{cite journal | vauthors = Sylvester JE, Fischel-Ghodsian N, Mougey EB, O'Brien TW | title = Mitochondrial ribosomal proteins: candidate genes for mitochondrial disease | journal = Genetics in Medicine | volume = 6 | issue = 2 | pages = 73–80 | date = March 2003 | pmid = 15017329 | doi = 10.1097/01.GIM.0000117333.21213.17 | s2cid = 22169585 | doi-access = free }}</ref> |
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== Function == |
== Function == |
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Mitochondria contain around 1000 proteins in [[yeast]] and 1500 proteins in [[Human|humans]]. However, only 8 and 13 proteins are encoded in [[mitochondrial DNA]] in yeast and humans respectively. Most mitochondrial proteins are synthesized via cytoplasmic ribosomes.<ref name="WenzOpaliński2015">{{cite journal| |
Mitochondria contain around 1000 proteins in [[yeast]] and 1500 proteins in [[Human|humans]]. However, only 8 and 13 proteins are encoded in [[mitochondrial DNA]] in yeast and humans respectively. Most mitochondrial proteins are synthesized via cytoplasmic ribosomes.<ref name="WenzOpaliński2015">{{cite journal | vauthors = Wenz LS, Opaliński Ł, Wiedemann N, BeckerT| title = Cooperation of protein machineries in mitochondrial protein sorting | journal = Biochimica et Biophysica Acta (BBA) - Molecular Cell Research | volume = 1853 | issue = 5 | pages = 1119–1129 | date = May 2015 | pmid = 25633533 | doi = 10.1016/j.bbamcr.2015.01.012 | doi-access = free }}</ref> Proteins that are key components in the [[electron transport chain]] are translated in mitochondria.<ref name="JohnstonWilliams2016">{{cite journal | vauthors = Johnston IG, Williams BP| title = Evolutionary Inference across Eukaryotes Identifies Specific Pressures Favoring Mitochondrial Gene Retention | journal = Cell Systems | volume = 2 | issue = 2 | pages = 101–111 | date = February 2016 | pmid = 27135164 | doi = 10.1016/j.cels.2016.01.013 | doi-access = free }}</ref><ref name="Hamers2016">{{cite journal| vauthors = HamersL|title=Why do our cell's power plants have their own DNA? |journal=Science |year=2016 |doi=10.1126/science.aaf4083 }}</ref> |
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== Structure == |
== Structure == |
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[[Mammals|Mammalian]] mitoribosomes have small 28S and large 39S subunits, together forming a 55S mitoribosome.<ref name="GreberBieri2015">{{ |
[[Mammals|Mammalian]] mitoribosomes have small 28S and large 39S subunits, together forming a 55S mitoribosome.<ref name="GreberBieri2015">{{cite journal | vauthors = Greber BJ, Bieri P, Leibundgut M, Leitner A, Aebersold R, Boehringer D, BanN | title = Ribosome. The complete structure of the 55S mammalian mitochondrial ribosome | journal = Science | volume = 348 | issue = 6232 | pages = 303–308 | date = April 2015 | pmid = 25837512 | doi = 10.1126/science.aaa3872 | hdl-access = free | s2cid = 206634178 | hdl = 20.500.11850/100390 }}</ref><ref name=":0">{{cite encyclopedia | vauthors = Spremulli LL|title=The Protein Biosynthetic Machinery of Mitochondria|date=2016-01-01 |encyclopedia=Encyclopedia of Cell Biology|pages=545–554| veditors = Bradshaw RA, Stahl PD |place= Waltham |publisher= Academic Press |doi=10.1016/b978-0-12-394447-4.10066-5 |isbn=978-0-12-394796-3 }}</ref> Plant mitoribosomes have small 33S and large 50S subunits, together forming a 78S mitoribosome.<ref name="GreberBieri2015" /><ref name=":0" /> |
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Animal mitoribosomes only have two rRNAs, 12S (SSU) and 16S (LSU), both highly |
[[Animal]] mitoribosomes only have two rRNAs, 12S (SSU) and 16S (LSU), both highly minimized compared to their larger homologues.<ref name="GreberBieri2015"/> Most eukaryotoes use [[5S ribosomal RNA#Presence in organelle ribosomes|5S mitoribosomal RNA]], animals, [[Fungus|fungi]], [[Alveolate|alveolates]] and [[Euglenozoa|euglenozoans]] being the exceptions.<ref name="Valach 2014">{{cite journal | vauthors = Valach M, Burger G, Gray MW, Lang BF | title = Widespread occurrence of organelle genome-encoded 5S rRNAs including permuted molecules | journal = Nucleic Acids Research | volume =42| issue =22| pages = 13764–13777 | date = December 2014 | pmid = 25429974 | pmc = 4267664 | doi = 10.1093/nar/gku1266 }}</ref> A variety of methods have evolved to fill in the gap left by a missing 5S, with animals co-opting a Mt-tRNA (Val in vertebrates).<ref name="GreberBieri2015"/><ref>{{cite journal | vauthors = Brown A, Amunts A, Bai XC, Sugimoto Y, Edwards PC, Murshudov G, Scheres SH, RamakrishnanV| display-authors =6| title = Structure of the large ribosomal subunit from human mitochondria | journal = Science | volume = 346 | issue = 6210 | pages = 718–722 | date = November 2014 | pmid = 25278503 | pmc = 4246062 | doi = 10.1126/science.1258026 | bibcode = 2014Sci...346..718B }}</ref> |
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== Comparison to other ribosomes == |
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Like mitochondria itself is descended from bacteria, mitochondrial ribosomes are descended from bacterial ribosomes.<ref name=":02">{{cite journal | vauthors = Greber BJ, Ban N | title = Structure and Function of the Mitochondrial Ribosome | journal = Annual Review of Biochemistry | volume = 85 | issue = 1 | pages = 103–132 | date = June 2016 | pmid = 27023846 | doi = 10.1146/annurev-biochem-060815-014343 | doi-access = free }}</ref> As mitochondria evolved however, the mitoribosome has significantly diverged from its bacterial cousins leading to differences in configuration and function.<ref name=":02" /> In configuration, the mitoribosome includes additional proteins in both its large and small subunits.<ref name=":02" /> In function, mitoribosomes are much more limited in the proteins they translate, only producing a few proteins, used mostly in the mitochondrial membrane. <ref name=":02" /> Below is a table showing some properties of different ribosomes: |
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{| class="wikitable" |
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|+Properties of mitoribosomes |
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! |
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!Bacteria<ref name=":02" /><ref name=":1">{{cite journal | vauthors = De Silva D, Tu YT, Amunts A, Fontanesi F, Barrientos A | title = Mitochondrial ribosome assembly in health and disease | journal = Cell Cycle | volume = 14 | issue = 14 | pages = 2226–2250 | date = 2015-07-18 | pmid = 26030272 | pmc = 4615001 | doi = 10.1080/15384101.2015.1053672 }}</ref> |
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!Cytosolic (Eukaryote)<ref name=":1" /><ref name=":02" /> |
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!Mammalian mitochondria<ref name=":02" /><ref name=":1" /> |
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!Yeast Mitochondria<ref name=":02" /><ref name=":1" /> |
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!Plant Mitochondria <ref>{{cite journal | vauthors = Robles P, Quesada V | title = Emerging Roles of Mitochondrial Ribosomal Proteins in Plant Development | journal = International Journal of Molecular Sciences | volume = 18 | issue = 12 | date = December 2017 | page = 2595 | pmid = 29207474 | pmc = 5751198 | doi = 10.3390/ijms18122595 | doi-access = free }}</ref> |
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|- |
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![[Sedimentation coefficient|Sedimentation Coefficient]] (LSU/SSU) |
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|70S (50S/30S) |
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|80S (60S/40S) |
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|55S (39S/28S) |
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|74S (54S/37S) |
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|~80S |
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|- |
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!Number of proteins (LSU/SSU) |
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|54 (33/21) |
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|79-80 (46-47/33) |
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|80 (50/30) |
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|84 (46/38) |
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|68-80 |
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|- |
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!Number of rRNAs (LSU/SSU) |
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|3 (2/1) |
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|4 (3/1) |
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|3 (2/1) |
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|2 (1/1) |
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|3 (2/1) |
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|} |
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== Diseases == |
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As the mitoribosome is responsible for the manufacture of proteins necessary for the [[electron transport chain]], malfunctions in the mitoribosome can result in metabolic disease.<ref name=":12">{{cite journal | vauthors = De Silva D, Tu YT, Amunts A, Fontanesi F, Barrientos A | title = Mitochondrial ribosome assembly in health and disease | journal = Cell Cycle | volume = 14 | issue = 14 | pages = 2226–2250 | date = 2015-07-18 | pmid = 26030272 | pmc = 4615001 | doi = 10.1080/15384101.2015.1053672 }}</ref> <ref name=":3" /> In humans, disease particularly manifests in energy-reliant organs such as the [[heart]], [[brain]], and [[Skeletal muscle|muscle]].<ref name=":3" /> Disease either originates from [[Mutation|mutations]] in mitochondrial rRNA or [[Gene|genes]] encoding the mitoribosomal proteins.<ref name=":3" /> In the case of mitoribosomal protein mutation, [[heredity]] of disease follows [[Mendelian inheritance]] as these proteins are encoded in the nucleus.<ref name=":12" /> On the other hand, because mitochondrial rRNA is encoded in the mitochondria, mutations in rRNA are maternally inherited.<ref name=":12" /> Examples of diseases in humans caused by these mutations include [[Leigh syndrome]], deafness, [[Neurological disorder|neurological disorders]], and various [[Cardiomyopathy|cardiomyopathies]].<ref name=":12" /> In [[Plant|plants]], mutation in mitoribosomal proteins can result in stunted size and distorted leaf growth.<ref name=":2">{{cite journal | vauthors = Robles P, Quesada V | title = Emerging Roles of Mitochondrial Ribosomal Proteins in Plant Development | journal = International Journal of Molecular Sciences | volume = 18 | issue = 12 | date = December 2017 | page = 2595 | pmid = 29207474 | pmc = 5751198 | doi = 10.3390/ijms18122595 | doi-access = free }}</ref> |
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== Genes == |
== Genes == |
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The mitochondrial ribosomal protein nomenclature generally follows that of bacteria, with extra numbers used for mitochondrion-specific proteins. (For more information on the nomenclature, see {{section link|Ribosomal protein|Table of ribosomal proteins}}.) |
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* [[MRPS1]], [[MRPS2]], [[MRPS3]], [[MRPS4]], [[MRPS5]], [[MRPS6]], [[MRPS7]], [[MRPS8]], [[MRPS9]], [[MRPS10]], [[MRPS11]], [[MRPS12]], [[MRPS13]], [[MRPS14]], [[MRPS15]], [[MRPS16]], [[MRPS17]], [[MRPS18]], [[MRPS19]], [[MRPS20]], [[MRPS21]], [[MRPS22]], [[MRPS23]], [[MRPS24]], [[MRPS25]], [[MRPS26]], [[MRPS27]], [[MRPS28]], [[MRPS29]], [[MRPS30]], [[MRPS31]], [[MRPS32]], [[MRPS33]], [[MRPS34]], [[MRPS35]] |
* [[MRPS1]], [[MRPS2]], [[MRPS3]], [[MRPS4]], [[MRPS5]], [[MRPS6]], [[MRPS7]], [[MRPS8]], [[MRPS9]], [[MRPS10]], [[MRPS11]], [[MRPS12]], [[MRPS13]], [[MRPS14]], [[MRPS15]], [[MRPS16]], [[MRPS17]], [[MRPS18]], [[MRPS19]], [[MRPS20]], [[MRPS21]], [[MRPS22]], [[MRPS23]], [[MRPS24]], [[MRPS25]], [[MRPS26]], [[MRPS27]], [[MRPS28]], [[MRPS29]], [[MRPS30]], [[MRPS31]], [[MRPS32]], [[MRPS33]], [[MRPS34]], [[MRPS35]] |
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* [[MRPL1]], [[MRPL2]], [[MRPL3]], [[MRPL4]], [[MRPL5]], [[MRPL6]], [[MRPL7]], [[MRPL8]], [[MRPL9]], [[MRPL10]], [[MRPL11]], [[MRPL12]], [[MRPL13]], [[MRPL14]], [[MRPL15]], [[MRPL16]], [[MRPL17]], [[MRPL18]], [[MRPL19]], [[MRPL20]], [[MRPL21]], [[MRPL22]], [[MRPL23]], [[MRPL24]], [[MRPL25]], [[MRPL26]], [[MRPL27]], [[MRPL28]], [[MRPL29]], [[MRPL30]], [[MRPL31]], [[MRPL32]], [[MRPL33]], [[MRPL34]], [[MRPL35]], [[MRPL36]], [[MRPL37]], [[MRPL38]], [[MRPL39]], [[MRPL40]], [[MRPL41]], [[MRPL42]] |
* [[MRPL1]], [[MRPL2]], [[MRPL3]], [[MRPL4]], [[MRPL5]], [[MRPL6]], [[MRPL7]], [[MRPL8]], [[MRPL9]], [[MRPL10]], [[MRPL11]], [[MRPL12]], [[MRPL13]], [[MRPL14]], [[MRPL15]], [[MRPL16]], [[MRPL17]], [[MRPL18]], [[MRPL19]], [[MRPL20]], [[MRPL21]], [[MRPL22]], [[MRPL23]], [[MRPL24]], [[MRPL25]], [[MRPL26]], [[MRPL27]], [[MRPL28]], [[MRPL29]], [[MRPL30]], [[MRPL31]], [[MRPL32]], [[MRPL33]], [[MRPL34]], [[MRPL35]], [[MRPL36]], [[MRPL37]], [[MRPL38]], [[MRPL39]], [[MRPL40]], [[MRPL41]], [[MRPL42]] |
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* rRNA: [[MT-RNR1]], [[MT-RNR2]] |
* rRNA: [[MT-RNR1]], [[MT-RNR2]], [[MT-TV (mitochondrial)]] |
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== References == |
== References == |
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{{Reflist}} |
{{Reflist}} |
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== Further reading == |
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* {{cite journal | vauthors = Greber BJ, Ban N | title = Structure and Function of the Mitochondrial Ribosome | journal = Annual Review of Biochemistry | volume = 85 | pages = 103–132 | date = June 2016 | pmid = 27023846 | doi = 10.1146/annurev-biochem-060815-014343 | doi-access = free }} |
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{{GeneticTranslation}} |
{{GeneticTranslation}} |
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[[Category:Ribosomal proteins| ]] |
[[Category:Ribosomal proteins| ]] |
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[[Category:Mitochondrial genetics]] |
[[Category:Mitochondrial genetics]] |
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{{molecular-cell-biology-stub}} |
{{molecular-cell-biology-stub}} |
The mitochondrial ribosome, or mitoribosome, is a protein complex that is active in mitochondria and functions as a riboprotein for translating mitochondrial mRNAs encoded in mtDNA. The mitoribosome is attached to the inner mitochondrial membrane.[1] Mitoribosomes, like cytoplasmic ribosomes, consist of two subunits — large (mt-LSU) and small (mt-SSU).[2] Mitoribosomes consist of several specific proteins and fewer rRNAs.[2] While mitochondrial rRNAs are encoded in the mitochondrial genome, the proteins that make up mitoribosomes are encoded in the nucleus and assembled by cytoplasmic ribosomes before being implanted into the mitochondria.[3]
Mitochondria contain around 1000 proteins in yeast and 1500 proteins in humans. However, only 8 and 13 proteins are encoded in mitochondrial DNA in yeast and humans respectively. Most mitochondrial proteins are synthesized via cytoplasmic ribosomes.[4] Proteins that are key components in the electron transport chain are translated in mitochondria.[5][6]
Mammalian mitoribosomes have small 28S and large 39S subunits, together forming a 55S mitoribosome.[7][8] Plant mitoribosomes have small 33S and large 50S subunits, together forming a 78S mitoribosome.[7][8]
Animal mitoribosomes only have two rRNAs, 12S (SSU) and 16S (LSU), both highly minimized compared to their larger homologues.[7] Most eukaryotoes use 5S mitoribosomal RNA, animals, fungi, alveolates and euglenozoans being the exceptions.[9] A variety of methods have evolved to fill in the gap left by a missing 5S, with animals co-opting a Mt-tRNA (Val in vertebrates).[7][10]
Like mitochondria itself is descended from bacteria, mitochondrial ribosomes are descended from bacterial ribosomes.[1] As mitochondria evolved however, the mitoribosome has significantly diverged from its bacterial cousins leading to differences in configuration and function.[1] In configuration, the mitoribosome includes additional proteins in both its large and small subunits.[1] In function, mitoribosomes are much more limited in the proteins they translate, only producing a few proteins, used mostly in the mitochondrial membrane. [1] Below is a table showing some properties of different ribosomes:
Bacteria[1][11] | Cytosolic (Eukaryote)[11][1] | Mammalian mitochondria[1][11] | Yeast Mitochondria[1][11] | Plant Mitochondria [12] | |
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Sedimentation Coefficient (LSU/SSU) | 70S (50S/30S) | 80S (60S/40S) | 55S (39S/28S) | 74S (54S/37S) | ~80S |
Number of proteins (LSU/SSU) | 54 (33/21) | 79-80 (46-47/33) | 80 (50/30) | 84 (46/38) | 68-80 |
Number of rRNAs (LSU/SSU) | 3 (2/1) | 4 (3/1) | 3 (2/1) | 2 (1/1) | 3 (2/1) |
As the mitoribosome is responsible for the manufacture of proteins necessary for the electron transport chain, malfunctions in the mitoribosome can result in metabolic disease.[13] [3] In humans, disease particularly manifests in energy-reliant organs such as the heart, brain, and muscle.[3] Disease either originates from mutations in mitochondrial rRNA or genes encoding the mitoribosomal proteins.[3] In the case of mitoribosomal protein mutation, heredity of disease follows Mendelian inheritance as these proteins are encoded in the nucleus.[13] On the other hand, because mitochondrial rRNA is encoded in the mitochondria, mutations in rRNA are maternally inherited.[13] Examples of diseases in humans caused by these mutations include Leigh syndrome, deafness, neurological disorders, and various cardiomyopathies.[13]Inplants, mutation in mitoribosomal proteins can result in stunted size and distorted leaf growth.[14]
The mitochondrial ribosomal protein nomenclature generally follows that of bacteria, with extra numbers used for mitochondrion-specific proteins. (For more information on the nomenclature, see Ribosomal protein § Table of ribosomal proteins.)
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Proteins |
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Other concepts |
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Ribosomal RNA / ribosome subunits
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Archaea (70S) |
Small (30S): | ||||||
Bacteria (70S) |
Small (30S): | ||||||
Eukaryotes |
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Ribosomal proteins | (See article table) |
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