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Limulus Clotting Factor C
Limulus clotting factor overbar C (, ''factor C'', ''limulus factor C'') is an enzyme. This enzyme catalyses the following chemical reaction : Selective cleavage of -Arg103-Ser- and -Ile124-Ile- bonds in limulus clotting factor B to form ''factor overbar B''. : Cleavage of -Pro-Arg- bonds in synthetic substrates This enzyme is isolated from the hemocyte granules of the horseshoe crabs Limulus and Tachypleus, where is serves as a LPS endotoxin-sensitive trypsin type serine protease to protect the organism from bacterial infection, initiating a cascade leading to coagulin formation. From the N-terminus to the C-terminus, the domains are: * EGF-like domain * 3 Sushi domains * one LCCL domain and one C-type lectin domain * 2 more Sushi domains * a trypsin domain This enzyme is useful in Limulus amebocyte lysate Limulus amebocyte lysate (LAL) is an aqueous extract of blood cells (amoebocytes) from the Atlantic horseshoe crab ''Limulus polyphemus''. LAL reacts with bacterial ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Enzyme
Enzymes () are proteins that act as biological catalysts by accelerating chemical reactions. The molecules upon which enzymes may act are called substrates, and the enzyme converts the substrates into different molecules known as products. Almost all metabolic processes in the cell need enzyme catalysis in order to occur at rates fast enough to sustain life. Metabolic pathways depend upon enzymes to catalyze individual steps. The study of enzymes is called ''enzymology'' and the field of pseudoenzyme analysis recognizes that during evolution, some enzymes have lost the ability to carry out biological catalysis, which is often reflected in their amino acid sequences and unusual 'pseudocatalytic' properties. Enzymes are known to catalyze more than 5,000 biochemical reaction types. Other biocatalysts are catalytic RNA molecules, called ribozymes. Enzymes' specificity comes from their unique three-dimensional structures. Like all catalysts, enzymes increase the reaction ra ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Organism
In biology, an organism () is any living system that functions as an individual entity. All organisms are composed of cells (cell theory). Organisms are classified by taxonomy into groups such as multicellular animals, plants, and fungi; or unicellular microorganisms such as protists, bacteria, and archaea. All types of organisms are capable of reproduction, growth and development, maintenance, and some degree of response to stimuli. Beetles, squids, tetrapods, mushrooms, and vascular plants are examples of multicellular organisms that differentiate specialized tissues and organs during development. A unicellular organism may be either a prokaryote or a eukaryote. Prokaryotes are represented by two separate domains – bacteria and archaea. Eukaryotic organisms are characterized by the presence of a membrane-bound cell nucleus and contain additional membrane-bound compartments called organelles (such as mitochondria in animals and plants ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
C-type Lectin
A C-type lectin (CLEC) is a type of carbohydrate-binding protein known as a lectin. The C-type designation is from their requirement for calcium for binding. Proteins that contain C-type lectin domains have a diverse range of functions including cell-cell adhesion, immune response to pathogens and apoptosis. Classification Drickamer ''et al.'' classified C-type lectins into 7 subgroups (I to VII) based on the order of the various protein domains in each protein. This classification was subsequently updated in 2002, leading to seven additional groups (VIII to XIV). Most recently, three further subgroups were added (XV to XVII). CLECs include: * CLEC1A, CLEC1B * CLEC2A, CLEC2B, CD69 (CLEC2C), CLEC2D, CLEC2L * CLEC3A, CLEC3B * CLEC4A, CLEC4C, CLEC4D, CLEC4E, CLEC4F, CLEC4G, ASGR1 (CLEC4H1), ASGR2 (CLEC4H2), FCER2 (CLEC4J), CD207 (CLEC4K), CD209 (CLEC4L), CLEC4M * CLEC5A * CLEC6A * CLEC7A * OLR1 (CLEC8A) * CLEC9A * CLEC10A * CLEC11A * CLEC12A, CLEC12B * CD302 (C ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
LCCL Domain
In molecular biology, the LCCL domain is a protein domain which has been named after several well-characterised proteins that were found to contain it, namely Limulus clotting factor C, Cochlin (Coch-5b2) and Lgl1 ( CRISPLD2). It is an about 100 amino acids domain whose C-terminal part contains a highly conserved histidine in a conserved motif YxxxSxxCxAAVHxGVI. The LCCL module is thought to be an autonomously folding domain that has been used for the construction of various modular proteins through exon-shuffling. It has been found in various metazoan proteins in association with complement B-type domains, C-type lectin domains, von Willebrand type A domains, CUB domains, discoidin lectin domains or CAP domains. It has been proposed that the LCCL domain could be involved in lipopolysaccharide (LPS) binding. LCCL exhibits a novel fold. Some proteins known to contain a LCCL domain include Limulus factor C, an LPS endotoxin-sensitive trypsin type serine protease which serve ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sushi Domain
Sushi domain is an evolutionarily conserved protein domain. It is also known as Complement control protein (CCP) modules or short consensus repeats (SCR). The name derives from the visual similarity of the domain to nigiri sushi when the primary structure is drawn showing the loops created by the disulfide bonds. Sushi domains exist in a wide variety of complement and adhesion proteins. The structure is known for this domain; it is based on a beta-sandwich arrangement - one face made up of three β-strands hydrogen-bonded to form a triple-stranded region at its centre, and the other face formed from two separate β-strands. CD21 (also called C3d receptor, CR2, Epstein Barr virus receptor or EBV-R) is the receptor for EBV and for C3d, C3dg and iC3b. Complement components may activate B cells through CD21. CD21 is part of a large signal-transduction complex that also involves CD19, CD81, and Leu13. Some of the proteins in this group are responsible for the molecular basis of t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Epidermal Growth Factor Family
The EGF-like domain is an evolutionary conserved protein domain, which derives its name from the epidermal growth factor where it was first described. It comprises about 30 to 40 amino-acid residues and has been found in a large number of mostly animal proteins. Most occurrences of the EGF-like domain are found in the extracellular domain of membrane-bound proteins or in proteins known to be secreted. An exception to this is the prostaglandin-endoperoxide synthase. The EGF-like domain includes 6 cysteine residues which in the epidermal growth factor have been shown to form 3 disulfide bonds. The structures of 4-disulfide EGF-domains have been solved from the laminin and integrin proteins. The main structure of EGF-like domains is a two-stranded β-sheet followed by a loop to a short C-terminal, two-stranded β-sheet. These two β-sheets are usually denoted as the major (N-terminal) and minor (C-terminal) sheets. EGF-like domains frequently occur in numerous tandem copies in p ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Coagulin
Coagulin is a gel-forming protein of hemolymph that hinders the spread of invaders by immobilising them. It is produced in the coagulogen form before being cleaved into the active form. In human medicine, coagulation of coagulin is the basis of detection of bacterial endotoxin in the LAL test for parenteral medications. The protein contains a single 175-residue polypeptide chain that is cleaved after Arg-18 and Arg-46 by a Limulus clotting enzyme contained in the hemocyte and activated by a bacterial endotoxin (lipopolysaccharide). Cleavage releases two chains of coagulin, A and B, linked by two disulfide bonds, together with the peptide C. Gel formation results from interlinking of coagulin molecules. The full-length structure of a coagulogen is known (); it shares the same cystine-knot cytokine superfamily (fold) as neurotrophins, with several cystines conserved. The A-B fold wraps around the helical peptide C, forming a compact structure. In crustaceans, hemolymph coagulati ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Bacteria
Bacteria (; singular: bacterium) are ubiquitous, mostly free-living organisms often consisting of one biological cell. They constitute a large domain of prokaryotic microorganisms. Typically a few micrometres in length, bacteria were among the first life forms to appear on Earth, and are present in most of its habitats. Bacteria inhabit soil, water, acidic hot springs, radioactive waste, and the deep biosphere of Earth's crust. Bacteria are vital in many stages of the nutrient cycle by recycling nutrients such as the fixation of nitrogen from the atmosphere. The nutrient cycle includes the decomposition of dead bodies; bacteria are responsible for the putrefaction stage in this process. In the biological communities surrounding hydrothermal vents and cold seeps, extremophile bacteria provide the nutrients needed to sustain life by converting dissolved compounds, such as hydrogen sulphide and methane, to energy. Bacteria also live in symbiotic and parasitic relationsh ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Serine Protease
Serine proteases (or serine endopeptidases) are enzymes that cleave peptide bonds in proteins. Serine serves as the nucleophilic amino acid at the (enzyme's) active site. They are found ubiquitously in both eukaryotes and prokaryotes. Serine proteases fall into two broad categories based on their structure: chymotrypsin-like (trypsin-like) or subtilisin-like. Classification The MEROPS protease classification system counts 16 superfamilies (as of 2013) each containing many families. Each superfamily uses the catalytic triad or dyad in a different protein fold and so represent convergent evolution of the catalytic mechanism. The majority belong to the S1 family of the PA clan (superfamily) of proteases. For superfamilies, P: superfamily, containing a mixture of nucleophile class families, S: purely serine proteases. superfamily. Within each superfamily, families are designated by their catalytic nucleophile, (S: serine proteases). Substrate specificity Serine ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Catalysis
Catalysis () is the process of increasing the rate of a chemical reaction by adding a substance known as a catalyst (). Catalysts are not consumed in the reaction and remain unchanged after it. If the reaction is rapid and the catalyst recycles quickly, very small amounts of catalyst often suffice; mixing, surface area, and temperature are important factors in reaction rate. Catalysts generally react with one or more reactants to form intermediates that subsequently give the final reaction product, in the process of regenerating the catalyst. Catalysis may be classified as either homogeneous, whose components are dispersed in the same phase (usually gaseous or liquid) as the reactant, or heterogeneous, whose components are not in the same phase. Enzymes and other biocatalysts are often considered as a third category. Catalysis is ubiquitous in chemical industry of all kinds. Estimates are that 90% of all commercially produced chemical products involve catalysts at some s ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Trypsin
Trypsin is an enzyme in the first section of the small intestine that starts the digestion of protein molecules by cutting these long chains of amino acids into smaller pieces. It is a serine protease from the PA clan superfamily, found in the digestive system of many vertebrates, where it hydrolyzes proteins. Trypsin is formed in the small intestine when its proenzyme form, the trypsinogen produced by the pancreas, is activated. Trypsin cuts peptide chains mainly at the carboxyl side of the amino acids lysine or arginine. It is used for numerous biotechnological processes. The process is commonly referred to as trypsin proteolysis or trypsinization, and proteins that have been digested/treated with trypsin are said to have been trypsinized. Trypsin was discovered in 1876 by Wilhelm Kühne and was named from the Ancient Greek word for rubbing since it was first isolated by rubbing the pancreas with glycerin. Function In the duodenum, trypsin catalyzes the hydrolysis of pept ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Tachypleus
''Tachypleus'' is a genus of south, southeast and east Asian horseshoe crabs in the family Limulidae. Species There are two extant (living) species: * ''Tachypleus gigas'' ( Müller, 1785) * ''Tachypleus tridentatus'' (Leach, 1819) And two extinct species only known from fossil. * ''Tachypleus decheni'' (Zincken, 1862) Upper Eocene Domsen Sands, Germany * ''Tachypleus syriacus'' (Woodward, 1879) Upper Cretaceous (Cenomanian The Cenomanian is, in the ICS' geological timescale, the oldest or earliest age of the Late Cretaceous Epoch or the lowest stage of the Upper Cretaceous Series. An age is a unit of geochronology; it is a unit of time; the stage is a unit in the s ...) Haqel and Hjoula Konservat-Lagerstatten, Lebanon References External links * Xiphosura Extant Cenomanian first appearances Chelicerate genera Taxonomy articles created by Polbot {{Chelicerata-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
