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Triple Helix
In the fields of geometry and biochemistry, a triple helix (plural triple helices) is a set of three congruent geometrical helices with the same axis, differing by a translation along the axis. This means that each of the helices keeps the same distance from the central axis. As with a single helix, a triple helix may be characterized by its pitch, diameter, and handedness. Examples of triple helices include triplex DNA, triplex RNA, the collagen helix, and collagen-like proteins. Structure A triple helix is named such because it is made up of three separate helices. Each of these helices shares the same axis, but they do not take up the same space because each helix is translated angularly around the axis. Generally, the identity of a triple helix depends on the type of helices that make it up. For example: a triple helix made of three strands of collagen protein is a collagen triple helix, and a triple helix made of three strands of DNA is a DNA triple helix. As with ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Collagen (triple Helix Protein)
Collagen () is the main structural protein in the extracellular matrix found in the body's various connective tissues. As the main component of connective tissue, it is the most abundant protein in mammals, making up from 25% to 35% of the whole-body protein content. Collagen consists of amino acids bound together to form a triple helix of elongated fibril known as a collagen helix. It is mostly found in connective tissue such as cartilage, bones, tendons, ligaments, and skin. Depending upon the degree of biomineralization, mineralization, collagen tissues may be rigid (bone) or compliant (tendon) or have a gradient from rigid to compliant (cartilage). Collagen is also abundant in corneas, blood vessels, the Gut (anatomy), gut, intervertebral discs, and the dentin in teeth. In muscle tissue, it serves as a major component of the endomysium. Collagen constitutes one to two percent of muscle tissue and accounts for 6% of the weight of the skeletal muscle tissue. The fibroblast is t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Post-translational Modification
Post-translational modification (PTM) is the covalent and generally enzymatic modification of proteins following protein biosynthesis. This process occurs in the endoplasmic reticulum and the golgi apparatus. Proteins are synthesized by ribosomes translating mRNA into polypeptide chains, which may then undergo PTM to form the mature protein product. PTMs are important components in cell signaling, as for example when prohormones are converted to hormones. Post-translational modifications can occur on the amino acid side chains or at the protein's C- or N- termini. They can extend the chemical repertoire of the 20 standard amino acids by modifying an existing functional group or introducing a new one such as phosphate. Phosphorylation is a highly effective mechanism for regulating the activity of enzymes and is the most common post-translational modification. Many eukaryotic and prokaryotic proteins also have carbohydrate molecules attached to them in a process cal ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Geometric Shapes
Geometric Shapes is a Unicode block of 96 symbols at code point range U+25A0–25FF. U+25A0–U+25CF The BLACK CIRCLE is displayed when typing in a password field, in order to hide characters from a screen recorder or shoulder surfing. U+25D0–U+25FF The CIRCLE WITH LEFT HALF BLACK is used to represent the contrast ratio of a screen. Font coverage Font sets like Code2000 and the DejaVu family include coverage for each of the glyphs in the Geometric Shapes range. Unifont also contains all the glyphs. Among the fonts in widespread use, full implementation is provided by Segoe UI Symbol and significant partial implementation of this range is provided by Arial Unicode MS and Lucida Sans Unicode, which include coverage for 83% (80 out of 96) and 82% (79 out of 96) of the symbols, respectively. Block Emoji The Geometric Shapes block contains eight emoji: U+25AA–U+25AB, U+25B6, U+25C0 and U+25FB–U+25FE. The block has sixteen standardized variants defined to spec ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Curves
A curve is a geometrical object in mathematics. Curve(s) may also refer to: Arts, entertainment, and media Music * Curve (band), an English alternative rock music group * ''Curve'' (album), a 2012 album by Our Lady Peace * "Curve" (song), a 2017 song by Gucci Mane featuring The Weeknd * ''Curve'', a 2001 album by Doc Walker * "Curve", a song by John Petrucci from '' Suspended Animation'', 2005 * "Curve", a song by Cam'ron from the album '' Crime Pays'', 2009 Periodicals * ''Curve'' (design magazine), an industrial design magazine * ''Curve'' (magazine), a U.S. lesbian magazine Other uses in arts, entertainment, and media * ''Curve'' (film), a 2015 film * BBC Two 'Curve' idents, various animations based around a curve motif Brands and enterprises *Curve (payment card), a payment card that aggregates multiple payment cards * Curve (theatre), a theatre in Leicester, United Kingdom * Curve, fragrance by Liz Claiborne * BlackBerry Curve, a series of phones from Researc ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
MALAT1
MALAT 1 (metastasis associated lung adenocarcinoma transcript 1) also known as NEAT2 (noncoding nuclear-enriched abundant transcript 2) is a large, infrequently spliced non-coding RNA, which is highly conserved amongst mammals and highly expressed in the nucleus. MALAT1 was identified in multiple types of physiological processes, such as alternative splicing, nuclear organization, epigenetic modulating of gene expression, and a number of evidences indicate that MALAT1 also closely relate to various pathological processes, ranging from diabetes complications to cancers. It regulates the expression of metastasis-associated genes. It also positively regulates cell motility via the transcriptional and/or post-transcriptional regulation of motility-related genes. MALAT1 may play a role in temperature-dependent sex determination in the Red-eared slider turtle (''Trachemys scripta''). Expression in alcoholic brains Transcripts of MALAT1 are significantly increased in the cerebellum of ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Telomere
A telomere (; ) is a region of repetitive nucleotide sequences associated with specialized proteins at the ends of linear chromosomes. Although there are different architectures, telomeres, in a broad sense, are a widespread genetic feature most commonly found in eukaryotes. In most, if not all species possessing them, they protect the terminal regions of chromosomal DNA from progressive degradation and ensure the integrity of linear chromosomes by preventing DNA repair systems from mistaking the very ends of the DNA strand for a double-strand break. Discovery In the early 1970s, Soviet theorist Alexei Olovnikov first recognized that chromosomes could not completely replicate their ends; this is known as the "end replication problem". Building on this, and accommodating Leonard Hayflick's idea of limited somatic cell division, Olovnikov suggested that DNA sequences are lost every time a cell replicates until the loss reaches a critical level, at which point cell division e ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Telomerase
Telomerase, also called terminal transferase, is a ribonucleoprotein that adds a species-dependent telomere repeat sequence to the 3' end of telomeres. A telomere is a region of repetitive sequences at each end of the chromosomes of most eukaryotes. Telomeres protect the end of the chromosome from DNA damage or from fusion with neighbouring chromosomes. The fruit fly ''Drosophila melanogaster'' lacks telomerase, but instead uses retrotransposons to maintain telomeres. Telomerase is a reverse transcriptase enzyme that carries its own RNA molecule (e.g., with the sequence 3′- CCC AA UCCC-5′ in ''Trypanosoma brucei'') which is used as a template when it elongates telomeres. Telomerase is active in gametes and most cancer cells, but is normally absent from, or at very low levels in, most somatic cells. History The existence of a compensatory mechanism for telomere shortening was first found by Soviet biologist Alexey Olovnikov in 1973, who also suggested the telomere hypo ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
S-Adenosyl Methionine
''S''-Adenosyl methionine (SAM), also known under the commercial names of SAMe, SAM-e, or AdoMet, is a common cosubstrate involved in methyl group transfers, transsulfuration, and aminopropylation. Although these anabolic reactions occur throughout the body, most SAM is produced and consumed in the liver. More than 40 methyl transfers from SAM are known, to various substrates such as nucleic acids, proteins, lipids and secondary metabolites. It is made from adenosine triphosphate (ATP) and methionine by methionine adenosyltransferase. SAM was first discovered by Giulio Cantoni in 1952. In bacteria, SAM is bound by the SAM riboswitch, which regulates genes involved in methionine or cysteine biosynthesis. In eukaryotic cells, SAM serves as a regulator of a variety of processes including DNA, tRNA, and rRNA methylation; immune response; amino acid metabolism; transsulfuration; and more. In plants, SAM is crucial to the biosynthesis of ethylene, an important plant hormo ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Riboswitch
In molecular biology, a riboswitch is a regulatory segment of a messenger RNA molecule that binds a small molecule, resulting in a change in production of the proteins encoded by the mRNA. Thus, an mRNA that contains a riboswitch is directly involved in regulating its own activity, in response to the concentrations of its effector molecule. The discovery that modern organisms use RNA to bind small molecules, and discriminate against closely related analogs, expanded the known natural capabilities of RNA beyond its ability to code for proteins, catalyze reactions, or to bind other RNA or protein macromolecules. The original definition of the term "riboswitch" specified that they directly sense small-molecule metabolite concentrations. Although this definition remains in common use, some biologists have used a broader definition that includes other cis-regulatory RNAs. However, this article will discuss only metabolite-binding riboswitches. Most known riboswitches occur in ba ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Twisted Intercalating Nucleic Acid
Twisted intercalating nucleic acid (TINA) is a nucleic acid molecule that, when added to triplex-forming oligonucleotides (TFOs), stabilizes Hoogsteen triplex DNA formation from double-stranded DNA (dsDNA) and TFOs. Its ability to twist around a triple bond increases ease of intercalation within double stranded DNA in order to form triplex DNA. Certain configurations have been shown to stabilize Watson-Crick antiparallel duplex DNA. TINA-DNA primers have been shown to increase the specificity of binding in PCR. The use of TINA insertions in G-quadruplexes has also been shown to enhance anti-HIV-1 activity. TINA stabilized PT demonstrates improved sensitivity and specificity of DNA based clinical diagnostic assays. Triplex DNA Triple helixes are formed when a single-stranded triplex-forming oligonucleotide (TFO) binds to a purine-containing strand of dsDNA through specific major groove interactions. Generally, the third-strand affinity of a TFO is low, due to the requirement ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Oligonucleotide
Oligonucleotides are short DNA or RNA molecules, oligomers, that have a wide range of applications in genetic testing, research, and forensics. Commonly made in the laboratory by solid-phase chemical synthesis, these small bits of nucleic acids can be manufactured as single-stranded molecules with any user-specified sequence, and so are vital for artificial gene synthesis, polymerase chain reaction (PCR), DNA sequencing, molecular cloning and as molecular probes. In nature, oligonucleotides are usually found as small RNA molecules that function in the regulation of gene expression (e.g. microRNA), or are degradation intermediates derived from the breakdown of larger nucleic acid molecules. Oligonucleotides are characterized by the sequence of nucleotide residues that make up the entire molecule. The length of the oligonucleotide is usually denoted by " -mer" (from Greek ''meros'', "part"). For example, an oligonucleotide of six nucleotides (nt) is a hexamer, while one of 25 nt w ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hydrophobic Effect
The hydrophobic effect is the observed tendency of nonpolar substances to aggregate in an aqueous solution and exclude water molecules. The word hydrophobic literally means "water-fearing", and it describes the segregation of water and nonpolar substances, which maximizes hydrogen bonding between molecules of water and minimizes the area of contact between water and nonpolar molecules. In terms of thermodynamics, the hydrophobic effect is the free energy change of water surrounding a solute. A positive free energy change of the surrounding solvent indicates hydrophobicity, whereas a negative free energy change implies hydrophilicity. The hydrophobic effect is responsible for the separation of a mixture of oil and water into its two components. It is also responsible for effects related to biology, including: cell membrane and vesicle formation, protein folding, insertion of membrane proteins into the nonpolar lipid environment and protein- small molecule associations. Hence th ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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