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Mitochondrial tRNA

Mitochondrial myopathy, encephalopathy, lactic acidosis, and stroke like episodes (MELAS) Mitochondrial tRNA (leu)... [Pg.636]

Mitochondrial diseases are often expressed as neuropathies and myopathies because brain and muscle are highly dependent on oxidative phosphorylation. Mitochondrial genes code for some of the components of the electron transport chain and oxidative phosphorylation, as well as some mitochondrial tRNA molecules. [Pg.96]

All eukaryotic cells in our bodies contain the same 23 chromosomes with the same DNA base sequences. The lone differences are the mitochondria. The mitochondria in typical somatic cells contain less than 0.1% of the cell s DNA but in fertilized and dividing egg cells this number is greater. mtDNA is much smaller, often containing fewer than 20,000 base pairs. The value for humans is 16,569 base pairs. The mtDNA is a circular duplex. mDNA codes for the mitochondrial tRNAs and rRNAs but only a fraction of the mitochondrial proteins. Over 95% of the mitochondrial proteins are encoded by nuclear DNA. The mitochondria divide when the cell divides. [Pg.341]

MERRF (myoclonic epilepsy with ragged red fibers) Is characterized by weakness on exertion, ataxia, and associated deafness and Is due to mutation of the mitochondrial tRNA gene. [Pg.191]

Mitochondrial DNA codes for the mitochondrial tRNAs and rRNAs and for a few mitochondrial proteins. More than 95% of mitochondrial proteins are encoded by nuclear DNA. Mitochondria and chloroplasts divide when the cell divides. Their DNA is replicated before and during division, and the daughter DNA molecules pass into the daughter organelles. [Pg.928]

The genetic code differs very little between species. By contrast, considerable differences occur between species in the anticodon translation system of tRNA, as evidenced by the mitochondrial tRNA system. In all systems the bases in the anticodon-codon complex run antiparallel, as in standard double-helix pairing, and in all cases only Watson-Cricklike base pairing occurs between the first two bases in the codon and the opposing bases in the anticodon segment of the tRNA. However, for the 3 base in the codon, the rules for pairing vary with the species and with the base in question. These rules, summarized in table 29.4, are as follows. [Pg.741]

J3. James, A. M., Sheard, R W., Wei, Y. H., and Murphy, M. P., Decreased ATP synthesis is phe-notypically expressed during increased energy demand in fibroblasts containing mitochondrial tRNA mutations. Eur. J. Biochem. 259, 462-469 (1999). [Pg.121]

Nucleoside Methylation is Responsible for Correct Folding of a Human Mitochondrial tRNA... [Pg.5]

Fig. 1.1.2. Naturally occurring modified nucleoside 1-methyladenosine is necessary for adoption of the biologically active cloverleaf fold of mitochondrial tRNA (m A,... Fig. 1.1.2. Naturally occurring modified nucleoside 1-methyladenosine is necessary for adoption of the biologically active cloverleaf fold of mitochondrial tRNA (m A,...
Bhattacharyya SN, Chatterjee S, Goswami S, Tripathi G, Dey SN, Adhya S (2003) Ping-pong interactions between mitochondrial tRNA import receptors within a multiprotein complex. Mol Cell Biol 23 5217-5224... [Pg.195]

The number of mammalian mitochondrial tRNA molecules is 22, which is less than the minimum number (32) needed to translate the universal code. This is possible because in each of the fourfold redundant sets—e.g., the four alanine codons GCU, GCC, GCA, and GCG—only one tRNA molecule (rather than two, as explained above) is used. In each set of four tRNA molecules, the base in the wobble position of the anticodon is U or a modified U (not I). It is not yet known whether this U is base-paired in the codon-anticodon interaction or manages to pair weakly with each of the four possible bases. For those codon sets that are doubly redundant—e.g., the two histidine codons CAU and CAC—the wobble base always forms, a G-U pair, as in the universal code. The structure of the human mitrochondrial tRNA molecule is also different from that of the standard tRNA molecule (except for mitochondrial tRNA UUX). (X = any nucleotide.) The most notable differences are the following ... [Pg.573]

The universal sequence CTt/tCXA is lacking in mitochondrial tRNA. [Pg.573]

In standard tRNA molecules, each of these bases participates in bonds that produce the folded L-shaped molecule. Thus, the mitochondrial tRNA molecule seems to be stabilized by fewer interactions. The three-dimensional configurations of these molecules are not known with certainty possibly they differ from the standard L-shape, and mitochondrial tRNA engages in a different type of interaction with the ribosome than standard tRNA molecules do. [Pg.573]

Since nucleic acids generally cannot go in and out of mitochondria, all mitochondria appear to code for their own rRNAs and tRNAs. For the same reason, only the mRNAs that have been transcribed from the mitochondrial genome are translated in the mitochondria. A unique feature of mitochondrial mRNAs is the lack of a m G cap at the 5 end (reviewed by Bag, 1991). There are only 22-25 tRNA species in the mitochondria, indicating that a single tRNA can recognize more than one codon. There are some structural and sequence differences in the mitochondrial tRNAs. Furthermore, deviations from the standard genetic code, for example, utilization of AUA as the initiation codon instead of AUG, and reading UGA as a tryptophan instead of a stop codon, are a unique feature of mitochondria (Lapointe... [Pg.257]

Watanabe and coworkers have investigated the structure and function of human mitochondrial tRNAs containing wobble modifications derived from taurine, the nucleosides 5-taurinomethyluridine (rniU) and 5-taurinomethyl-2-thiouridine Mutations that affect the modification of the tRNA are associated... [Pg.675]

Hancock K, Hajduk SL. The mitochondrial tRNAs of Trypanosoma brucei are nuclear encoded. J Biol Chem 1990 265(31) 19208-15. [Pg.18]


See other pages where Mitochondrial tRNA is mentioned: [Pg.308]    [Pg.401]    [Pg.401]    [Pg.108]    [Pg.719]    [Pg.1042]    [Pg.231]    [Pg.1692]    [Pg.740]    [Pg.98]    [Pg.99]    [Pg.100]    [Pg.101]    [Pg.114]    [Pg.185]    [Pg.735]    [Pg.231]    [Pg.573]    [Pg.573]    [Pg.441]    [Pg.577]    [Pg.675]    [Pg.675]    [Pg.690]    [Pg.719]    [Pg.1042]    [Pg.111]    [Pg.779]    [Pg.390]    [Pg.90]    [Pg.758]    [Pg.93]    [Pg.10]   
See also in sourсe #XX -- [ Pg.135 , Pg.139 , Pg.143 , Pg.144 , Pg.148 , Pg.150 ]




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