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Brachyspira Holin Family
The ''Brachyspira'' holin (B-Hol) FamilyTC# 1.E.55 consists of several proteins from the GTA holin of ''Brachyspira hyodysenteriae''TC# 1.E.55.1.1, which facilitates gene transfer agent-release (see also GTA holin family) to VSH-1 holin of ''Brachyspira pilosicoli.'' VSH-1 is thought to participate in cell lysis. These proteins range in size from about 85 to 145 amino acyl residues (aas) and exhibit between 2 and 4 transmembrane segments (TMSs). A representative list of proteins belonging to the B-Hol family can be found in thTransporter Classification Database See also * Holin * Lysin Lysins, also known as endolysins or murein hydrolases, are hydrolytic enzymes produced by bacteriophages in order to cleave the host's cell wall during the final stage of the lytic cycle. Lysins are highly evolved enzymes that are able to target ... * Transporter Classification Database Further reading * Matson, Eric G.; Thompson, M. Greg; Humphrey, Samuel B.; Zuerner, Richard L.; Stanton, ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Brachyspira
''Brachyspira'' is a genus of bacteria classified within the phylum Spirochaetota.See the List of Prokaryotic names with Standing in Nomenclature. Data extracted from See the NCBIbr>webpage on SpirochaetesData extracted from ''Brachyspira species'' include pathogens in pigs, birds, dogs, and humans. '' B. pilosicoli'' colonizes millions of humans worldwide, leading to human intestinal spirochaetosis, a chronic, intermittent watery diarrhea vastly underdiagnosed because of the lack of a simple diagnostic tool for clinicians. Multiplex qPCRs are promising diagnostic tools, as Brachyspira do not grow on conventional media. '' B. pilosicoli'' also cause avian spirochetosis: birds might be considered as the natural reservoir. '' B. hyodysenteriae'' leads to diarrheal disease in growing pigs worldwide, causing the so-called swine dysentery, typhlocolitis or porcine intestinal spirochaetosis, which contributes to major "production losses" in agrobusiness. Some species like ' ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Gene Transfer Agent-release Holin Family
Gene transfer agent-release holins (GTA-HolTC# 1.E.54 are holins which are believed to facilitate the lysis-dependent release of a gene transfer agent. Particularly the gene transfer agent of ''Rhodobacter capsulatus'' (RcGTA), which is known to be a bacteriophage-like genetic element that induces horizontal gene transfer. The promoter of the RcGTA gene was identified by Westbye ''et al''. in 2013. A representative list of members belonging to the GTA-Hol family can be found in the Transporter Classification Database with homologues found in Pseudomonadota (formerly proteobacteria) and caudovirales. See also * Gene transfer agent * Lysin Lysins, also known as endolysins or murein hydrolases, are hydrolytic enzymes produced by bacteriophages in order to cleave the host's cell wall during the final stage of the lytic cycle. Lysins are highly evolved enzymes that are able to targ ... References Further reading * * * * * Holins {{membrane-protein-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Brachyspira Pilosicoli
''Brachyspira pilosicoli'' is a gram-negative, anaerobic, host-associated spirochete that colonizes the intestinal tract of animals and humans. It appears as a characteristic "false brush border" due to its end-on attachment to enterocytes of the colon where it interferes with intestinal absorption. ''B. pilosicoli'' is unique from other '' Brachyspira'' species because it colonizes a variety of domestic animals including pigs, chickens, dogs, wild birds, rodents, and humans. It is the causative agent of intestinal spirochetosis in pigs, chickens and humans. In particular, ''B. pilosicoli'' has been described as an important colonic pathogen of pigs and chickens, causing colitis and diarrhea resulting in depressed rates of growth and impaired production on farms where infections with ''B. pilosicoli'' may be endemic. Bacterial attachment disrupts the colonic enterocytes and associated villi, causing the symptoms characteristic of intestinal spirochetosis. Additionally, ''B. pil ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Holin
Holins are a diverse group of small proteins produced by dsDNA bacteriophages in order to trigger and control the degradation of the host's cell wall at the end of the lytic cycle. Holins form pores in the host's cell membrane, allowing lysins to reach and degrade peptidoglycan, a component of bacterial cell walls. Holins have been shown to regulate the timing of lysis with great precision. Over 50 unrelated gene families encode holins, making them the most diverse group of proteins with common function. Together with lysins, holins are being studied for their potential use as antibacterial agents. While canonical holins act by forming large pores, pinholins such as the S protein of lambdoid phage 21 act by forming heptameric channels that depolarize the bacterial membrane. They are associated with SAR endolysins, which remain inactive in the periplasm prior to the depolarization of the membrane. Viruses that infect eukaryotic cells may use similar channel-forming proteins called ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Lysin
Lysins, also known as endolysins or murein hydrolases, are hydrolytic enzymes produced by bacteriophages in order to cleave the host's cell wall during the final stage of the lytic cycle. Lysins are highly evolved enzymes that are able to target one of the five bonds in peptidoglycan (murein), the main component of bacterial cell walls, which allows the release of progeny virions from the lysed cell. Cell-wall-containing Archaea are also lysed by specialized pseudomurein-cleaving lysins, while most archaeal viruses employ alternative mechanisms. Similarly, not all bacteriophages synthesize lysins: some small single-stranded DNA and RNA phages produce membrane proteins that activate the host's autolytic mechanisms such as autolysins. Lysins are being used as antibacterial agents due to their high effectiveness and specificity in comparison with antibiotics, which are susceptible to bacterial resistance. Structure Double-stranded DNA phage lysins tend to lie within the 25 to 40 ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Protein Families
A protein family is a group of evolutionarily related proteins. In many cases, a protein family has a corresponding gene family, in which each gene encodes a corresponding protein with a 1:1 relationship. The term "protein family" should not be confused with family as it is used in taxonomy. Proteins in a family descend from a common ancestor and typically have similar three-dimensional structures, functions, and significant sequence similarity. The most important of these is sequence similarity (usually amino-acid sequence), since it is the strictest indicator of homology and therefore the clearest indicator of common ancestry. A fairly well developed framework exists for evaluating the significance of similarity between a group of sequences using sequence alignment methods. Proteins that do not share a common ancestor are very unlikely to show statistically significant sequence similarity, making sequence alignment a powerful tool for identifying the members of protein familie ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Membrane Proteins
Membrane proteins are common proteins that are part of, or interact with, biological membranes. Membrane proteins fall into several broad categories depending on their location. Integral membrane proteins are a permanent part of a cell membrane and can either penetrate the membrane (transmembrane) or associate with one or the other side of a membrane ( integral monotopic). Peripheral membrane proteins are transiently associated with the cell membrane. Membrane proteins are common, and medically important—about a third of all human proteins are membrane proteins, and these are targets for more than half of all drugs. Nonetheless, compared to other classes of proteins, determining membrane protein structures remains a challenge in large part due to the difficulty in establishing experimental conditions that can preserve the correct conformation of the protein in isolation from its native environment. Function Membrane proteins perform a variety of functions vital to the surv ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Transmembrane Proteins
A transmembrane protein (TP) is a type of integral membrane protein that spans the entirety of the cell membrane. Many transmembrane proteins function as gateways to permit the transport of specific substances across the membrane. They frequently undergo significant conformational changes to move a substance through the membrane. They are usually highly hydrophobic and aggregate and precipitate in water. They require detergents or nonpolar solvents for extraction, although some of them (beta-barrels) can be also extracted using denaturing agents. The peptide sequence that spans the membrane, or the transmembrane segment, is largely hydrophobic and can be visualized using the hydropathy plot. Depending on the number of transmembrane segments, transmembrane proteins can be classified as single-span (or bitopic) or multi-span (polytopic). Some other integral membrane proteins are called monotopic, meaning that they are also permanently attached to the membrane, but do not pass t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Transmembrane Transporters
A transmembrane protein (TP) is a type of integral membrane protein that spans the entirety of the cell membrane. Many transmembrane proteins function as gateways to permit the transport of specific substances across the membrane. They frequently undergo significant conformational changes to move a substance through the membrane. They are usually highly hydrophobic and aggregate and precipitate in water. They require detergents or nonpolar solvents for extraction, although some of them (beta-barrels) can be also extracted using denaturing agents. The peptide sequence that spans the membrane, or the transmembrane segment, is largely hydrophobic and can be visualized using the hydropathy plot. Depending on the number of transmembrane segments, transmembrane proteins can be classified as single-span (or bitopic) or multi-span (polytopic). Some other integral membrane proteins are called monotopic, meaning that they are also permanently attached to the membrane, but do not pass t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Transport Proteins
A transport protein (variously referred to as a transmembrane pump, transporter, escort protein, acid transport protein, cation transport protein, or anion transport protein) is a protein that serves the function of moving other materials within an organism. Transport proteins are vital to the growth and life of all living things. There are several different kinds of transport proteins. Carrier proteins are proteins involved in the movement of ions, small molecules, or macromolecules, such as another protein, across a biological membrane. Carrier proteins are integral membrane proteins; that is, they exist within and span the membrane across which they transport substances. The proteins may assist in the movement of substances by facilitated diffusion (i.e., passive transport) or active transport. These mechanisms of movement are known as carrier-mediated transport. Each carrier protein is designed to recognize only one substance or one group of very similar substances. Research ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Integral Membrane Proteins
An integral, or intrinsic, membrane protein (IMP) is a type of membrane protein that is permanently attached to the biological membrane. All ''transmembrane proteins'' are IMPs, but not all IMPs are transmembrane proteins. IMPs comprise a significant fraction of the proteins encoded in an organism's genome. Proteins that cross the membrane are surrounded by annular lipids, which are defined as lipids that are in direct contact with a membrane protein. Such proteins can only be separated from the membranes by using detergents, nonpolar solvents, or sometimes denaturing agents. Structure Three-dimensional structures of ~160 different integral membrane proteins have been determined at atomic resolution by X-ray crystallography or nuclear magnetic resonance spectroscopy. They are challenging subjects for study owing to the difficulties associated with extraction and crystallization. In addition, structures of many water-soluble protein domains of IMPs are available in the Prote ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
