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Dihydrouridine
Dihydrouridine (abbreviated as D, DHU, or UH2) is a pyrimidine nucleoside which is the result of adding two hydrogen atoms to a uridine, making it a fully saturated pyrimidine ring with no remaining double bonds. D is found in tRNA and rRNA molecules as a nucleoside; the corresponding nucleobase is 5,6-dihydrouracil. Because it is non-planar, D disturbs the stacking interactions in helices and destabilizes the RNA structure. D also stabilizes the C2′- ''endo'' sugar conformation, which is more flexible than the C3′-''endo'' conformation; this effect is propagated to the 5′-neighboring residue. Thus, while pseudouridine and 2′-O-methylations stabilize the local RNA structure, D does the opposite. The tRNAs of organisms that grow at low temperatures (psychrophile Psychrophiles or cryophiles (adj. ''psychrophilic'' or ''cryophilic'') are extremophile, extremophilic organisms that are capable of cell growth, growth and reproduction in low temperatures, ranging from ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Nucleobase
Nucleotide bases (also nucleobases, nitrogenous bases) are nitrogen-containing biological compounds that form nucleosides, which, in turn, are components of nucleotides, with all of these monomers constituting the basic building blocks of nucleic acids. The ability of nucleobases to form base pairs and to stack one upon another leads directly to long-chain helical structures such as ribonucleic acid (RNA) and deoxyribonucleic acid (DNA). Five nucleobases— adenine (A), cytosine (C), guanine (G), thymine (T), and uracil (U)—are called ''primary'' or ''canonical''. They function as the fundamental units of the genetic code, with the bases A, G, C, and T being found in DNA while A, G, C, and U are found in RNA. Thymine and uracil are distinguished by merely the presence or absence of a methyl group on the fifth carbon (C5) of these heterocyclic six-membered rings. In addition, some viruses have aminoadenine (Z) instead of adenine. It differs in having an extra amine group, ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
TRNA
Transfer ribonucleic acid (tRNA), formerly referred to as soluble ribonucleic acid (sRNA), is an adaptor molecule composed of RNA, typically 76 to 90 nucleotides in length (in eukaryotes). In a cell, it provides the physical link between the genetic code in messenger RNA (mRNA) and the amino acid sequence of proteins, carrying the correct sequence of amino acids to be combined by the protein-synthesizing machinery, the ribosome. Each three-nucleotide codon in mRNA is complemented by a three-nucleotide anticodon in tRNA. As such, tRNAs are a necessary component of translation, the biological synthesis of new proteins in accordance with the genetic code. Overview The process of translation starts with the information stored in the nucleotide sequence of DNA. This is first transformed into mRNA, then tRNA specifies which three-nucleotide codon from the genetic code corresponds to which amino acid. Each mRNA codon is recognized by a particular type of tRNA, which docks to it along ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
5,6-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] |
Biochemistry (journal)
''Biochemistry'' is a peer-reviewed academic journal in the field of biochemistry. Founded in 1962, the journal is now published weekly by the American Chemical Society, with 51 or 52 annual issues. According to the ''Journal Citation Reports'', the journal has a 2022 impact factor of 2.9. The previous editor-in-chief was Richard N. Armstrong ( Vanderbilt University School of Medicine) (2004–2016). After his death, Alanna Schepartz (UC Berkeley) was appointed editor-in-chief An editor-in-chief (EIC), also known as lead editor or chief editor, is a publication's editorial leader who has final responsibility for its operations and policies. The editor-in-chief heads all departments of the organization and is held accoun .... (accessed May 24, 2017) Indexing ''Biochemistry'' i ...[...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Psychrophile
Psychrophiles or cryophiles (adj. ''psychrophilic'' or ''cryophilic'') are extremophile, extremophilic organisms that are capable of cell growth, growth and reproduction in low temperatures, ranging from to . They are found in places that are permanently cold, such as the polar regions and the deep sea. They can be contrasted with thermophiles, which are organisms that thrive at unusually high temperatures, and mesophiles at intermediate temperatures. Psychrophile is Greek for 'cold-loving', . Many such organisms are bacteria or archaea, but some eukaryotes such as lichens, snow algae, phytoplankton, fungi, and Chironomidae, wingless midges, are also classified as psychrophiles. Biology Habitat The cold environments that psychrophiles inhabit are ubiquitous on Earth, as a large fraction of the planetary surface experiences temperatures lower than 10 °C. They are present in permafrost, polar ice, glaciers, snow field, snowfields and deep ocean waters. These organisms can a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Free Text
Free may refer to: Concept * Freedom, the ability to act or change without constraint or restriction * Emancipate, attaining civil and political rights or equality * Free (''gratis''), free of charge * Gratis versus libre, the difference between the two common meanings of the adjective "free". Computing * Free (programming), a function that releases dynamically allocated memory for reuse * Free software, software usable and distributable with few restrictions and no payment *, an emoji in the Enclosed Alphanumeric Supplement block. Mathematics * Free object ** Free abelian group ** Free algebra ** Free group ** Free module ** Free semigroup * Free variable People * Free (surname) * Free (rapper) (born 1968), or Free Marie, American rapper and media personality * Free, a pseudonym for the activist and writer Abbie Hoffman * Free (active 2003–), American musician in the band FreeSol Arts and media Film and television * ''Free'' (film), a 2001 American dramedy * '' F ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
RNA Structure
Nucleic acid structure refers to the structure of nucleic acids such as DNA and RNA. Chemically speaking, DNA and RNA are very similar. Nucleic acid structure is often divided into four different levels: primary, secondary, tertiary, and quaternary. Primary structure Primary structure consists of a linear sequence of nucleotides that are linked together by phosphodiester bonds. It is this linear sequence of nucleotides that make up the primary structure of DNA or RNA. Nucleotides consist of 3 components: # Nitrogenous base ## Adenine ## Guanine ## Cytosine ## Thymine (present in DNA only) ## Uracil (present in RNA only) # 5-carbon sugar which is called deoxyribose (found in DNA) and ribose (found in RNA). # One or more phosphate groups. The nitrogen bases adenine and guanine are purine in structure and form a glycosidic bond between their 9 nitrogen and the 1' -OH group of the deoxyribose. Cytosine, thymine, and uracil are pyrimidines, hence the glycosidic bonds form between ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
2′-O-methylation
2'-''O''-methylation (2'-''O''-Me) is a common nucleotide epitranscriptomics modification of ribosomal RNA (rRNA). The rRNA is transcribed from DNA and then used to create proteins through translation. The resulting protein would normally be solely dependent on the gene it was translated from, but the methylation of the RNA would influence the outcome of the protein as well. This modification to the rRNA is done via ribonucleoprotein (snoRNP) where a methyl group is added to the 2' hydroxyl of the ribose moiety of any nucleotide (Nm) producing a methoxy group. The modification of one Nm creates more stabilization in the structure by 0.2kcal/mol which is more enthalpically favorable. 2'-''O''-methylated nucleotides are mostly found in post-translational ribosomal RNA and small nuclear RNA located in the ribosome and spliceosome. Currently, about 55 2'-''O''-methylations have been identified in yeast alone and 106 in humans and deposited in RNA Modification Base (RMBase) database ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Pseudouridine
Pseudouridine (5-ribosyluracil, abbreviated by the Greek letter psi- Ψ) is an isomer of the nucleoside uridine in which the uracil is attached via a carbon-carbon instead of a nitrogen-carbon glycosidic bond. Pseudouridine is the most abundant RNA modification in cellular RNA and one of over 100 chemically distinct modifications that may affect translation or other functions of RNA. Pseudouridine is the C5-glycoside isomer of uridine that contains a C-C bond between C1 of the ribose sugar and C5 of uracil, rather than usual C1-N1 bond found in uridine. Uridine is converted to pseudouridine by rotating the uridine molecule 180° across its N3-C6 axis. The C-C bond gives it more rotational freedom and conformational flexibility. In addition, pseudouridine has an extra hydrogen bond donor at the N1 position. Pseudouridine is a ubiquitous constituent of structural RNA ( transfer (tRNA), ribosomal (rRNA), small nuclear (snRNA), and small nucleolar (snoRNA)), and present in messe ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Stacking (chemistry)
In chemistry, stacking refers to superposition of molecules or atomic sheets owing to attractive interactions between these molecules or sheets. Metal dichalcogenide compounds Metal dichalcogenides have the formula ME2, where M = a transition metal and E = S, Se, Te. In terms of their electronic structures, these compounds are usually viewed as derivatives of M4+. They adopt stacked structures, which is relevant to their ability to undergo intercalation, e.g. by lithium, and their lubricating properties. The corresponding diselenides and even ditellurides are known, e.g., TiSe2, MoSe2, and WSe2. Charge transfer salts A combination of tetracyanoquinodimethane (TCNQ) and tetrathiafulvalene (TTF) forms a strong charge-transfer complex referred to as ''TTF-TCNQ''. The solid shows almost metallic electrical conductance. In a TTF-TCNQ crystal, TTF and TCNQ molecules are arranged independently in separate parallel-aligned stacks, and an electron transfer occurs from donor (TTF ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
