3 research outputs found
Complete chemical structures of human mitochondrial tRNAs
Mitochondria generate most cellular energy via oxidative phosphorylation. Twenty-two species of mitochondrial (mt-)tRNAs encoded in mtDNA translate essential subunits of the respiratory chain complexes. mt-tRNAs contain post-transcriptional modifications introduced by nuclear-encoded tRNA-modifying enzymes. They are required for deciphering genetic code accurately, as well as stabilizing tRNA. Loss of tRNA modifications frequently results in severe pathological consequences. Here, we perform a comprehensive analysis of post-transcriptional modifications of all human mt-tRNAs, including 14 previously-uncharacterized species. In total, we find 18 kinds of RNA modifications at 137 positions (8.7% in 1575 nucleobases) in 22 species of human mt-tRNAs. An up-to-date list of 34 genes responsible for mt-tRNA modifications are provided. We identify two genes required for queuosine (Q) formation in mt-tRNAs. Our results provide insight into the molecular mechanisms underlying the decoding system and could help to elucidate the molecular pathogenesis of human mitochondrial diseases caused by aberrant tRNA modifications
Room-Temperature Pressure-Induced Nanostructural CuInTe<sub>2</sub> Thermoelectric Material with Low Thermal Conductivity
A room-temperature
high-pressure synthesis method is proposed as an alternative way to
induce nanoscale structural disorder in the bulk thermoelectric CuInTe<sub>2</sub> matrix. This disorder stems from the coexistence of distinct
domains with different degrees and geometries of disorder at Cu/In
cation sites. The lattice thermal conductivity of high-pressure-treated
CuInTe<sub>2</sub> is substantially less than that of hot-pressed
CuInTe<sub>2</sub>. The Debye–Callaway model reveals that the
reduced lattice thermal conductivity is mainly attributed to disorder
at the Cu/In cation sites and stacking faults, which were probably
created during formation of the high-pressure-treated phases. This
study demonstrates that room-temperature high-pressure synthesis can
produce a radical change in the crystal structure and physical properties
of conventional thermoelectric materials