Cholesterol-dependent Cytolysin
The thiol-activated Cholesterol-dependent Cytolysin (CDC) familyTC# 1.C.12 is a member of the MACPF superfamily. Cholesterol dependent cytolysins are a family of β-barrel pore-forming exotoxins that are secreted by gram-positive bacteria. CDCs are secreted as water-soluble monomers of 50-70 kDa, that when bound to the target cell, form a circular homo-oligomeric complex containing as many as 40 (or more) monomers. Through multiple conformational changes, the β-barrel transmembrane structure (~250 Å in diameter depending on the toxin) is formed and inserted into the target cell membrane. The presence of cholesterol in the target membrane is required for pore formation, though the presence of cholesterol is not required by all CDCs for binding. For example, intermedilysin (ILYTC# 1.C.12.1.5 secreted by '' Streptococcus intermedius'' will bind only to target membranes containing a specific protein receptor, independent of the presence of cholesterol, but cholesterol is required by ...
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MACPF
The Membrane Attack Complex/Perforin (MACPF) superfamily, sometimes referred to as the MACPF/CDC superfamily, is named after a domain that is common to the membrane attack complex (MAC) proteins of the complement system (C6, C7, C8α, C8β and C9) and perforin (PF). Members of this protein family are pore-forming toxins (PFTs). In eukaryotes, MACPF proteins play a role in immunity and development. Archetypal members of the family are complement C9 and perforin, both of which function in human immunity. C9 functions by punching holes in the membranes of Gram-negative bacteria. Perforin is released by cytotoxic T cells and lyses virally infected and transformed cells. In addition, perforin permits delivery of cytotoxic proteases called granzymes that cause cell death. Deficiency of either protein can result in human disease. Structural studies reveal that MACPF domains are related to cholesterol-dependent cytolysins (CDCs), a family of pore forming toxins previously ...
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Proline
Proline (symbol Pro or P) is an organic acid classed as a proteinogenic amino acid (used in the biosynthesis of proteins), although it does not contain the amino group but is rather a secondary amine. The secondary amine nitrogen is in the protonated form (NH2+) under biological conditions, while the carboxyl group is in the deprotonated −COO− form. The "side chain" from the α carbon connects to the nitrogen forming a pyrrolidine loop, classifying it as a aliphatic amino acid. It is non-essential in humans, meaning the body can synthesize it from the non-essential amino acid L-glutamate. It is encoded by all the codons starting with CC (CCU, CCC, CCA, and CCG). Proline is the only proteinogenic amino acid which is a secondary amine, as the nitrogen atom is attached both to the α-carbon and to a chain of three carbons that together form a five-membered ring. History and etymology Proline was first isolated in 1900 by Richard Willstätter who obtained the amino a ...
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Amphipathic
In chemistry, an amphiphile (), or amphipath, is a chemical compound possessing both hydrophilic (''water-loving'', polar) and lipophilic (''fat-loving'', nonpolar) properties. Such a compound is called amphiphilic or amphipathic. Amphiphilic compounds include surfactants and detergents. The phospholipid amphiphiles are the major structural component of cell membranes. Amphiphiles are the basis for a number of areas of research in chemistry and biochemistry, notably that of lipid polymorphism. Organic compounds containing hydrophilic groups at both ends of the molecule are called bolaamphiphilic. The micelles they form in the aggregate are prolate. Structure The lipophilic group is typically a large hydrocarbon moiety, such as a long chain of the form CH3(CH2)n, with n > 4. The hydrophilic group falls into one of the following categories: # charged groups #* anionic. Examples, with the lipophilic part of the molecule represented by ''R'', are: #** carboxylates: RCO2− #** ...
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Hydrophobic Residues
Amino acids are organic compounds that contain both amino and carboxylic acid functional groups. Although over 500 amino acids exist in nature, by far the most important are the 22 α-amino acids incorporated into proteins. Only these 22 appear in the genetic code of life. Amino acids can be classified according to the locations of the core structural functional groups ( alpha- , beta- , gamma- amino acids, etc.); other categories relate to polarity, ionization, and side-chain group type (aliphatic, acyclic, aromatic, polar, etc.). In the form of proteins, amino-acid '' residues'' form the second-largest component (water being the largest) of human muscles and other tissues. Beyond their role as residues in proteins, amino acids participate in a number of processes such as neurotransmitter transport and biosynthesis. It is thought that they played a key role in enabling life on Earth and its emergence. Amino acids are formally named by the IUPAC- IUBMB Joint Commissio ...
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Alpha Helix
An alpha helix (or α-helix) is a sequence of amino acids in a protein that are twisted into a coil (a helix). The alpha helix is the most common structural arrangement in the Protein secondary structure, secondary structure of proteins. It is also the most extreme type of local structure, and it is the local structure that is most easily predicted from a sequence of amino acids. The alpha helix has a right-handed helix conformation in which every backbone amino, N−H group hydrogen bonds to the backbone carbonyl, C=O group of the amino acid that is four residue (biochemistry), residues earlier in the protein sequence. Other names The alpha helix is also commonly called a: * Pauling–Corey–Branson α-helix (from the names of three scientists who described its structure) * 3.613-helix because there are 3.6 amino acids in one ring, with 13 atoms being involved in the ring formed by the hydrogen bond (starting with amidic hydrogen and ending with carbonyl oxygen) Discovery ...
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Beta Hairpin
The beta hairpin (sometimes also called beta-ribbon or beta-beta unit) is a simple protein structural motif involving two beta strands that look like a Hairpin (fashion), hairpin. The motif consists of two strands that are adjacent in primary structure, oriented in an Antiparallel (biochemistry), antiparallel direction (the N-terminus of one sheet is adjacent to the C-terminus of the next), and linked by a short loop of two to five amino acids. Beta hairpins can occur in isolation or as part of a series of hydrogen bonded strands that collectively comprise a beta sheet. Researchers such as Francisco J. Blanco, Francisco Blanco ''et al.'' have used protein NMR to show that beta-hairpins can be formed from isolated short peptides in aqueous solution, suggesting that hairpins could form nucleation sites for protein folding. Classification Beta hairpins were originally categorized solely by the number of amino acid residues in their loop sequences, such that they were named one-resid ...
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Activation Energy
In the Arrhenius model of reaction rates, activation energy is the minimum amount of energy that must be available to reactants for a chemical reaction to occur. The activation energy (''E''a) of a reaction is measured in kilojoules per mole (kJ/mol) or kilocalories per mole (kcal/mol). Activation energy can be thought of as a magnitude of the potential barrier (sometimes called the energy barrier) separating minima of the potential energy surface pertaining to the initial and final thermodynamic state. For a chemical reaction to proceed at a reasonable rate, the temperature of the system should be high enough such that there exists an appreciable number of molecules with translational energy equal to or greater than the activation energy. The term "activation energy" was introduced in 1889 by the Swedish scientist Svante Arrhenius. Other uses Although less commonly used, activation energy also applies to nuclear reactions and various other physical phenomena. Temperature ...
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THM And Beta Subunits Of PFO D4
THM, Thm, thm or ThM may refer to: *Turbo-Hydramatic Turbo-Hydramatic or Turbo Hydra-Matic is the registered tradename for a family of automatic transmissions developed and produced by General Motors. These transmissions mate a three-element turbine torque converter to a Simpson planetary geartr ...

PFO Pre Pore And Pore
PFO may refer to: * Patent foramen ovale – a blood-flow pathway between a human heart's atriums, normally naturally closed after birth * Personal Freedom Outreach – an Evangelical organization opposing cults * Pittsburgh Film Office * IATA code for Paphos International Airport * Pathfinder Roleplaying Game The ''Pathfinder Roleplaying Game'' is a fantasy role-playing game (RPG) that was published in 2009 by Paizo Publishing. The first edition extends and modifies the System Reference Document (SRD) based on the revised 3rd edition ''Dungeons ... – online version * Persistent felony offender – a defendant accused under a three-strikes law * Hong Kong's Public Finance Ordinance {{disambiguation ...
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C-terminus
The C-terminus (also known as the carboxyl-terminus, carboxy-terminus, C-terminal tail, carboxy tail, C-terminal end, or COOH-terminus) is the end of an amino acid chain (protein Proteins are large biomolecules and macromolecules that comprise one or more long chains of amino acid residue (biochemistry), residues. Proteins perform a vast array of functions within organisms, including Enzyme catalysis, catalysing metab ... or polypeptide), terminated by a free carboxyl group (-COOH). When the protein is translated from messenger RNA, it is created from N-terminus to C-terminus. The convention for writing peptide sequences is to put the C-terminal end on the right and write the sequence from N- to C-terminus. Chemistry Each amino acid has a carboxyl group and an amine group. Amino acids link to one another to form a chain by a dehydration reaction which joins the amine group of one amino acid to the carboxyl group of the next. Thus polypeptide chains have an end with an ...
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Undecapeptide
Peptides are short chains of amino acids linked by peptide bonds. A polypeptide is a longer, continuous, unbranched peptide chain. Polypeptides that have a molecular mass of 10,000 Da or more are called proteins. Chains of fewer than twenty amino acids are called oligopeptides, and include dipeptides, tripeptides, and tetrapeptides. Peptides fall under the broad chemical classes of biological polymers and oligomers, alongside nucleic acids, oligosaccharides, polysaccharides, and others. Proteins consist of one or more polypeptides arranged in a biologically functional way, often bound to ligands such as coenzymes and cofactors, to another protein or other macromolecule such as DNA or RNA, or to complex macromolecular assemblies. Amino acids that have been incorporated into peptides are termed residues. A water molecule is released during formation of each amide bond.. All peptides except cyclic peptides have an N-terminal (amine group) and C-terminal (carboxyl group) residu ...
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Liposome
A liposome is a small artificial vesicle, spherical in shape, having at least one lipid bilayer. Due to their hydrophobicity and/or hydrophilicity, biocompatibility, particle size and many other properties, liposomes can be used as drug delivery vehicles for administration of pharmaceutical drugs and nutrients, such as lipid nanoparticles in mRNA vaccines, and DNA vaccines. Liposomes can be prepared by disrupting biological membranes (such as by sonication). Liposomes are most often composed of phospholipids, especially phosphatidylcholine, and cholesterol, but may also include other lipids, such as those found in egg and phosphatidylethanolamine, as long as they are compatible with lipid bilayer structure. A liposome design may employ surface ligands for attaching to desired cells or tissues. Based on vesicle structure, there are seven main categories for liposomes: multilamellar large (MLV), oligolamellar (OLV), small unilamellar (SUV), medium-sized unilamellar (MUV), larg ...
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