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Non-canonical Base Pairing
Non-canonical base pairing occurs when nucleobases hydrogen bond, or base pair, to one another in schemes other than the standard Watson-Crick base pairs (which are adenine (A) -- thymine (T) in DNA, adenine (A) -- uracil (U) in RNA, and guanine (G) -- cytosine (C) in both DNA and RNA). There are three main types of non-canonical base pairs: those stabilized by polar hydrogen bonds, those having interactions among C−H and O/N groups, and those that have hydrogen bonds between the bases themselves. The first discovered non-canonical base pairs are Hoogsteen base pairs, which were first described by American biochemist Karst Hoogsteen. Non-canonical base pairings commonly occur in the secondary structure of RNA (e.g. pairing of G with U), and in tRNA recognition. They are typically less stable than standard base pairings. The presence of non-canonical base pairs in double stranded DNA results in a disrupted double helix. History James Watson and Francis Crick published the do ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Nucleobase
Nucleobases, also known as ''nitrogenous bases'' or often simply ''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 ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Wobble in astronomy, also known as the ''wobble method''
{{disambiguation ...
Wobble or wobbles may refer to: * "Wobble" (song), a single by V.I.C. * Wobbles (equine disorder), a disorder of the nervous system in dogs and horses * Wobble base pair, a type of base pairing in genetics * Jah Wobble (born 1958), British musician * Milankovitch wobble, change in the Earth's axial tilt, axial precession and orbital eccentricity * Speed wobble, a quick oscillation of primarily just the steerable wheel(s) of a vehicle * A metasyntactic variable, commonly used alongside ''wibble'', ''wubble'', and ''flob'' See also * Wobbler (other) * Weeble, several lines of children's roly-poly toys * Doppler spectroscopy Doppler spectroscopy (also known as the radial-velocity method, or colloquially, the wobble method) is an indirect method for finding extrasolar planets and brown dwarfs from radial-velocity measurements via observation of Doppler shifts in t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Glycosidic Bond
A glycosidic bond or glycosidic linkage is a type of covalent bond that joins a carbohydrate (sugar) molecule to another group, which may or may not be another carbohydrate. A glycosidic bond is formed between the hemiacetal or hemiketal group of a saccharide (or a molecule derived from a saccharide) and the hydroxyl group of some compound such as an alcohol. A substance containing a glycosidic bond is a glycoside. The term 'glycoside' is now extended to also cover compounds with bonds formed between hemiacetal (or hemiketal) groups of sugars and several chemical groups other than hydroxyls, such as -SR (thioglycosides), -SeR (selenoglycosides), -NR1R2 (N-glycosides), or even -CR1R2R3 (C-glycosides). Particularly in naturally occurring glycosides, the compound ROH from which the carbohydrate residue has been removed is often termed the aglycone, and the carbohydrate residue itself is sometimes referred to as the 'glycone'. S-, N-, C-, and O-glycosidic bonds Glycosidi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hoogsteen Base Pair AU
A Hoogsteen base pair is a variation of base-pairing in nucleic acids such as the A•T pair. In this manner, two nucleobases, one on each strand, can be held together by hydrogen bonds in the major groove. A Hoogsteen base pair applies the N7 position of the purine base (as a hydrogen bond acceptor) and C6 amino group (as a donor), which bind the Watson–Crick (N3–C4) face of the pyrimidine base. History Ten years after James Watson and Francis Crick published their model of the DNA double helix, Karst Hoogsteen reported a crystal structure of a complex in which analogues of A and T formed a base pair that had a different geometry from that described by Watson and Crick. Similarly, an alternative base-pairing geometry can occur for G•C pairs. Hoogsteen pointed out that if the alternative hydrogen-bonding patterns were present in DNA, then the double helix would have to assume a quite different shape. Hoogsteen base pairs are observed in alternative structures such as the ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Wobble Base Pair
A wobble base pair is a pairing between two nucleotides in RNA molecules that does not follow Watson-Crick base pair rules. The four main wobble base pairs are guanine-uracil (G-U), hypoxanthine-uracil (I-U), hypoxanthine-adenine (I-A), and hypoxanthine-cytosine (I-C). In order to maintain consistency of nucleic acid nomenclature, "I" is used for hypoxanthine because hypoxanthine is the nucleobase of inosine; nomenclature otherwise follows the names of nucleobases and their corresponding nucleosides (e.g., "G" for both guanine and guanosine – as well as for deoxyguanosine). The thermodynamic stability of a wobble base pair is comparable to that of a Watson-Crick base pair. Wobble base pairs are fundamental in RNA secondary structure and are critical for the proper translation of the genetic code. Brief history In the genetic code, there are 43 = 64 possible codons (3 nucleotide sequences). For translation, each of these codons requires a tRNA molecule with an anticodon with whic ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Non-canonical Base Pairing Fig5
The adjective canonical is applied in many contexts to mean "according to the canon" the standard, rule or primary source that is accepted as authoritative for the body of knowledge or literature in that context. In mathematics, "canonical example" is often used to mean "archetype". Science and technology * Canonical form, a natural unique representation of an object, or a preferred notation for some object Mathematics * * Canonical coordinates, sets of coordinates that can be used to describe a physical system at any given point in time * Canonical map, a morphism that is uniquely defined by its main property * Canonical polyhedron, a polyhedron whose edges are all tangent to a common sphere, whose center is the average of its vertices * Canonical ring, a graded ring associated to an algebraic variety * Canonical injection, in set theory * Canonical representative, in set theory a standard member of each element of a set partition Differential geometry * Canonical one-form, ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Base Pair
A base pair (bp) is a fundamental unit of double-stranded nucleic acids consisting of two nucleobases bound to each other by hydrogen bonds. They form the building blocks of the DNA double helix and contribute to the folded structure of both DNA and RNA. Dictated by specific hydrogen bonding patterns, "Watson–Crick" (or "Watson–Crick–Franklin") base pairs (guanine–cytosine and adenine–thymine) allow the DNA helix to maintain a regular helical structure that is subtly dependent on its nucleotide sequence. The Complementarity (molecular biology), complementary nature of this based-paired structure provides a redundant copy of the genetic information encoded within each strand of DNA. The regular structure and data redundancy provided by the DNA double helix make DNA well suited to the storage of genetic information, while base-pairing between DNA and incoming nucleotides provides the mechanism through which DNA polymerase replicates DNA and RNA polymerase transcribes DNA in ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cis Trans Orientations Of Glycosidic Bond
Cis or cis- may refer to: Places * Cis, Trentino, in Italy * In Poland: ** Cis, Świętokrzyskie Voivodeship, south-central ** Cis, Warmian-Masurian Voivodeship, north Math, science and biology * cis (mathematics) (cis(''θ'')), a trigonometric mathematical function related to Euler's formula * ''Cis'' (beetle), genus * Cis–trans isomerism, in chemistry * cis-regulatory element, regions of non-coding DNA which regulate the transcription of nearby genes Other uses * Cisgender, in contrast with transgender * C♯ (musical note), known as cis See also * CIS (other) * * Ciss (other) Ciss (pronounced SIHS) is a Senegalese surname. Notable people with the surname include: * Amadou Ciss (born 1999), Senegalese footballer who plays for Fortuna Sittard *Elhadji Ciss Abdoulaye Elhadji Ciss (born 26 June 1994) is a Senegalese p ... * Csi (other) {{disambiguation, geo ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Nucleobase Edges
Nucleobases, also known as ''nitrogenous bases'' or often simply ''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 e ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Antibiotic
An antibiotic is a type of antimicrobial substance active against bacteria. It is the most important type of antibacterial agent for fighting bacterial infections, and antibiotic medications are widely used in the treatment and prevention of such infections. They may either kill or inhibit the growth of bacteria. A limited number of antibiotics also possess antiprotozoal activity. Antibiotics are not effective against viruses such as the common cold or influenza; drugs which inhibit viruses are termed antiviral drugs or antivirals rather than antibiotics. Sometimes, the term ''antibiotic''—literally "opposing life", from the Greek roots ἀντι ''anti'', "against" and βίος ''bios'', "life"—is broadly used to refer to any substance used against microbes, but in the usual medical usage, antibiotics (such as penicillin) are those produced naturally (by one microorganism fighting another), whereas non-antibiotic antibacterials (such as sulfonamides and antiseptics) ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Optical Rotatory Dispersion
Optical rotatory dispersion is the variation in the optical rotation of a substance with a change in the wavelength of light. Optical rotatory dispersion can be used to find the absolute configuration of metal complexes. For example, when plane-polarized white light from an overhead projector is passed through a cylinder of sucrose solution, a spiral rainbow is observed perpendicular to the cylinder. Principles of operation When white light passes through a polarizer, the extent of rotation of light depends on its wavelength. Short wavelengths are rotated more than longer wavelengths, per unit of distance. Because the wavelength of light determines its color, the variation of color with distance through the tube is observed. This dependence of specific rotation on wavelength is called optical rotatory dispersion. In all materials the rotation varies with wavelength. The variation is caused by two quite different phenomena. The first accounts in most cases for the majority of the ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
