|
Archaeosine
Archaeosine (G*) is a modified nucleoside found in the dihydrouracil loop at position 15 of tRNAs found in Archaea, and is thought to be important for the heat resistance of thermophilic archaea such as ''Thermococcus kodakarensis''. See also * Queuine Queuine () (Q) is a hypermodified nucleobase found in the first (or wobble) position of the anticodon of tRNAs specific for Asn, Asp, His, and Tyr, in most eukaryotes and prokaryotes. Because it is utilized by all eukaryotes but produced exclusiv ... References {{reflist Nucleosides Hydroxymethyl compounds ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Nucleoside
Nucleosides are glycosylamines that can be thought of as nucleotides without a phosphate group. A nucleoside consists simply of a nucleobase (also termed a nitrogenous base) and a five-carbon sugar (ribose or 2'-deoxyribose) whereas a nucleotide is composed of a nucleobase, a five-carbon sugar, and one or more phosphate groups. In a nucleoside, the anomeric carbon is linked through a glycosidic bond to the N9 of a purine or the N1 of a pyrimidine. Nucleotides are the molecular building-blocks of DNA and RNA. List of nucleosides and corresponding nucleobases The reason for 2 symbols, shorter and longer, is that the shorter ones are better for contexts where explicit disambiguation is superfluous (because context disambiguates) and the longer ones are for contexts where explicit disambiguation is judged to be needed or wise. For example, when discussing long nucleobase sequences in genomes, the CATG symbol system is much preferable to the Cyt-Ade-Thy-Gua symbol system (see '' N ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Dihydrouracil
Dihydrouracil is an intermediate in the catabolism of uracil. It is the base present in the nucleoside dihydrouridine. See also * Dihydrouracil dehydrogenase (NAD+) * Dihydrouracil oxidase * Dihydropyrimidinase In enzymology, a dihydropyrimidinase () is an enzyme that catalyzes the chemical reaction :5,6-dihydrouracil + H2O \rightleftharpoons 3-ureidopropanoate Thus, the two substrates of this enzyme are 5,6-dihydrouracil and H2O, whereas its produ ... References Nucleobases Ureas Pyrimidinediones {{organic-compound-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
TRNA
Transfer RNA (abbreviated tRNA and formerly referred to as sRNA, for soluble RNA) is an adaptor molecule composed of RNA, typically 76 to 90 nucleotides in length (in eukaryotes), that serves as the physical link between the mRNA and the amino acid sequence of proteins. tRNAs genes from Bacteria are typically shorter (mean = 77.6 bp) than tRNAs from Archaea (mean = 83.1 bp) and eukaryotes (mean = 84.7 bp). The mature tRNA follows an opposite pattern with tRNAs from Bacteria being usually longer (median = 77.6 nt) than tRNAs from Archaea (median = 76.8 nt), with eukaryotes exhibiting the shortest mature tRNAs (median = 74.5 nt). Transfer RNA (tRNA) does this by carrying an amino acid to the protein synthesizing machinery of a cell called the ribosome. Complementation of a 3-nucleotide codon in a messenger RNA (mRNA) by a 3-nucleotide anticodon of the tRNA results in protein synthesis based on the mRNA code. As such, tRNAs are a necessary component of translation, the biological ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Archaea
Archaea ( ; singular archaeon ) is a domain of single-celled organisms. These microorganisms lack cell nuclei and are therefore prokaryotes. Archaea were initially classified as bacteria, receiving the name archaebacteria (in the Archaebacteria kingdom), but this term has fallen out of use. Archaeal cells have unique properties separating them from the other two domains, Bacteria and Eukaryota. Archaea are further divided into multiple recognized phyla. Classification is difficult because most have not been isolated in a laboratory and have been detected only by their gene sequences in environmental samples. Archaea and bacteria are generally similar in size and shape, although a few archaea have very different shapes, such as the flat, square cells of ''Haloquadratum walsbyi''. Despite this morphological similarity to bacteria, archaea possess genes and several metabolic pathways that are more closely related to those of eukaryotes, notably for the enzymes involved ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Thermophilic
A thermophile is an organism—a type of extremophile—that thrives at relatively high temperatures, between . Many thermophiles are archaea, though they can be bacteria or fungi. Thermophilic eubacteria are suggested to have been among the earliest bacteria. Thermophiles are found in various geothermally heated regions of the Earth, such as hot springs like those in Yellowstone National Park (see image) and deep sea hydrothermal vents, as well as decaying plant matter, such as peat bogs and compost. Thermophiles can survive at high temperatures, whereas other bacteria or archaea would be damaged and sometimes killed if exposed to the same temperatures. The enzymes in thermophiles function at high temperatures. Some of these enzymes are used in molecular biology, for example the ''Taq'' polymerase used in PCR. "Thermophile" is derived from the el, θερμότητα (''thermotita''), meaning heat, and el, φίλια (''philia''), love. Classification Thermophiles can be c ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Thermococcus Kodakarensis
''Thermococcus kodakarensis'' is a species of thermophilic archaea. The type strain ''T. kodakarensis'' KOD1 is one of the best-studied members of the genus. History ''T. kodakarensis'' was isolated from a solfatara near the shore of Kodakara Island, Kagoshima, Japan. The isolate was originally named ''Pyrococcus kodakarensis'' KOD1, but reclassified as a species of ''Thermococcus'', based on 16S rRNA sequence. Early research with ''T. kodakarensis'' was directed mostly at its thermostable enzymes, but its relative ease of handling and genetic manipulation facilitated by natural competence has made it an attractive system for the study of several biological processes. Properties ''T. kodakarensis'' cells are irregular cocci 1–2 μm in diameter, often occurring in pairs, and are highly motile by means of lophotrichous archaella. The cell wall consists of a layer of diether and tetraether lipids, and an outer glycoprotein coat. ''T. kodakarensis'' is an obligat ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Queuine
Queuine () (Q) is a hypermodified nucleobase found in the first (or wobble) position of the anticodon of tRNAs specific for Asn, Asp, His, and Tyr, in most eukaryotes and prokaryotes. Because it is utilized by all eukaryotes but produced exclusively by bacteria, it is a putative vitamin. The nucleoside of queuine is queuosine. Queuine is not found in the tRNA of archaea; however, a related 7-deazaguanine derivative, the nucleoside of which is archaeosine, occurs in different tRNA position, the dihydrouridine loop, and in tRNAs with more specificities. History and naming In 1967, it was discovered that the four above-mentioned tRNAs contained an as-yet unknown nucleoside, which was designated "Nucleoside Q". This name remained in use throughout much of the work to characterize the compound, after which it was proposed that its common name should be based on the sound of the letter Q—thus producing "queuine" by analogy to guanine and other nucleobases, and "queuosine" by analog ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Nucleosides
Nucleosides are glycosylamines that can be thought of as nucleotides without a phosphate group. A nucleoside consists simply of a nucleobase (also termed a nitrogenous base) and a five-carbon sugar (ribose or 2'-deoxyribose) whereas a nucleotide is composed of a nucleobase, a five-carbon sugar, and one or more phosphate groups. In a nucleoside, the anomeric carbon is linked through a glycosidic bond to the N9 of a purine or the N1 of a pyrimidine. Nucleotides are the molecular building-blocks of DNA and RNA. List of nucleosides and corresponding nucleobases The reason for 2 symbols, shorter and longer, is that the shorter ones are better for contexts where explicit disambiguation is superfluous (because context disambiguates) and the longer ones are for contexts where explicit disambiguation is judged to be needed or wise. For example, when discussing long nucleobase sequences in genomes, the CATG symbol system is much preferable to the Cyt-Ade-Thy-Gua symbol system (see '' N ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
.jpg "Click for more on -> Archaea")
