|
C4b-binding Protein
C4b-binding protein (C4BP) is a protein complex involved in the complement system where it acts as inhibitor. C4BP has an octopus-like structure with a central stalk and seven branching alpha-chains. The main form of C4BP in human blood is composed of 7 identical alpha-chains and one unique beta-chain, which in turn binds anticoagulant, vitamin K-dependent protein S. C4BP is a large glycoprotein (500 kDa) with an estimated plasma concentration of 200 micrograms/mL synthesized mainly in the liver. The genes coding for C4BP α-chain (C4BPA) and β-chain (C4BPB) are located in the regulators of complement activation (RCA) gene cluster on the long arm of chromosome 1 in the vicinity of other complement inhibitors. Functions It inhibits the action the classical and the lectin pathways, more specifically C4. It also has ability to bind C3b. C4BP accelerates decay of C3-convertase and is a cofactor for serine protease factor I which cleaves C4b and C3b. C4BP binds apoptotic and n ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Protein Complex
A protein complex or multiprotein complex is a group of two or more associated polypeptide chains. Protein complexes are distinct from multienzyme complexes, in which multiple catalytic domains are found in a single polypeptide chain. Protein complexes are a form of quaternary structure. Proteins in a protein complex are linked by non-covalent protein–protein interactions. These complexes are a cornerstone of many (if not most) biological processes. The cell is seen to be composed of modular supramolecular complexes, each of which performs an independent, discrete biological function. Through proximity, the speed and selectivity of binding interactions between enzymatic complex and substrates can be vastly improved, leading to higher cellular efficiency. Many of the techniques used to enter cells and isolate proteins are inherently disruptive to such large complexes, complicating the task of determining the components of a complex. Examples of protein complexes include the p ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Serum Amyloid P Component
The serum amyloid P component (SAP) is the identical serum form of amyloid P component (AP), a 25kDa pentameric protein first identified as the pentagonal constituent of in vivo pathological deposits called "amyloid". APCS is its human gene. In amyloidosis AP makes up 14% of the dry mass of amyloid deposits and is thought to be an important contributor to the pathogenesis of a related group of diseases called the Amyloidoses. These conditions are characterised by the ordered aggregation of normal globular proteins and peptides into insoluble fibres which disrupt tissue architecture and are associated with cell death. AP is thought to decorate and stabilise aggregates by preventing proteolytic cleavage and hence inhibiting fibril removal via the normal protein scavenging mechanisms. This association is utilised in the routine clinical diagnostic technique of SAP scintigraphy whereby radio-labelled protein is injected into patients to locate areas of amyloid deposition. The SAP-a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Porin (protein)
Porins are beta barrel proteins that cross a cellular membrane and act as a pore, through which molecules can diffuse. Unlike other membrane transport proteins, porins are large enough to allow passive diffusion, i.e., they act as channels that are specific to different types of molecules. They are present in the outer membrane of gram-negative bacteria and some gram-positive mycobacteria (mycolic acid-containing actinomycetes), the outer membrane of mitochondria, and the outer chloroplast membrane (outer plastid membrane). Structure Porins are composed of beta sheets (β sheets) made up of beta strands (β strands) which are linked together by beta turns on the cytoplasmic side and long loops of amino acids on the other. The β strands lie in an antiparallel fashion and form a cylindrical tube, called a beta barrel (β barrel). The amino acid composition of the porin β strands are unique in that polar and nonpolar residues alternate along them. This means that the nonpolar ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Gonococcus
''Neisseria gonorrhoeae'', also known as ''gonococcus'' (singular), or ''gonococci'' (plural), is a species of Gram-negative diplococci bacteria isolated by Albert Neisser in 1879. It causes the sexually transmitted genitourinary infection gonorrhea as well as other forms of gonococcal disease including disseminated gonococcemia, septic arthritis, and gonococcal ophthalmia neonatorum. It is oxidase positive and aerobic, and it survives phagocytosis and grows inside neutrophils. Culturing it requires carbon dioxide supplementation and enriched agar (chocolate agar) with various antibiotics ( Thayer–Martin). It exhibits antigenic variation through genetic recombination of its pili and surface proteins that interact with the immune system. Sexual transmission is through vaginal, anal, or oral sex. Sexual transmission may be prevented through the use of barrier protection. Perinatal transmission may occur during childbirth, and may be prevented by antibiotic treatment of the ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
M Protein (Streptococcus)
M protein is a virulence factor that can be produced by certain species of ''Streptococcus''. Viruses, parasites and bacteria are covered in protein and sugar molecules that help them gain entry into a host by counteracting the host's defenses. One such molecule is the M protein produced by certain streptococcal bacteria. At its C-terminus within the cell wall, M proteins embody a motif that is now known to be shared by many Gram-positive bacterial surface proteins. The motif includes a conserved pentapeptide LPXTG, which precedes a hydrophobic C-terminal membrane spanning domain, which itself precedes a cluster of basic residues at the C-terminus. M protein is strongly anti-phagocytic and is the major virulence factor for group A streptococci (''Streptococcus pyogenes''). It binds to serum factor H, destroying C3-convertase and preventing opsonization by C3b. However plasma B cells can generate antibodies against M protein which will help in opsonization and further the d ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
PRELP
Prolargin is a protein that in humans is encoded by the ''PRELP'' gene. The protein encoded by this gene is a leucine-rich repeat protein present in connective tissue extracellular matrix. This protein functions as a molecule anchoring basement membranes to the underlying connective tissue. This protein has been shown to bind type I collagen to basement membranes and type II collagen to cartilage. It also binds the basement membrane heparan sulfate proteoglycan perlecan. This protein is suggested to be involved in the pathogenesis of Hutchinson–Gilford progeria (HGP), which is reported to lack the binding of collagen in basement membranes and cartilage. Alternatively spliced Alternative splicing, or alternative RNA splicing, or differential splicing, is an alternative splicing process during gene expression that allows a single gene to code for multiple proteins. In this process, particular exons of a gene may be ... transcript variants encoding the same protein have be ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Osteoadherin
Osteomodulin (also called osteoadherin or osteoadherin proteoglycan) is a protein that in humans is encoded by the ''OMD'' gene In biology, the word gene (from , ; "... Wilhelm Johannsen coined the word gene to describe the Mendelian units of heredity..." meaning ''generation'' or ''birth'' or ''gender'') can have several different meanings. The Mendelian gene is a b .... References Further reading * * * * * * * * * {{gene-9-stub Proteoglycans ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Fibromodulin
Fibromodulin is a protein that in humans is encoded by the ''FMOD'' gene. Fibromodulin is a 42kDa protein of a family of small interstitial leucine-rich repeat proteoglycans (SLRPs). It can have up to four N-linked keratan sulfate chains attached to the core protein within the leucine-rich region. It shares significant sequence homology with biglycan and decorin. Function Fibromodulin participates in the assembly of the collagen fibers of the extracellular matrix. It binds to the same site on the collagen type I molecule as lumican. It also inhibits fibrillogenesis of collagen type I and collagen type III ''in vitro''. It regulates TGF-beta activities by sequestering TGF-beta into the extracellular matrix. Clinical significance There is an age-dependent decline in the synthesis of keratan sulfate chains, so non-glycated forms of fibromodulin can accumulate in tissues such as cartilage. Fibromodulin is found in the epidermis of human skin and is expressed by skin cells (ker ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
C-reactive Protein
C-reactive protein (CRP) is an annular (ring-shaped) pentameric protein found in blood plasma, whose circulating concentrations rise in response to inflammation. It is an acute-phase protein of hepatic origin that increases following interleukin-6 secretion by macrophages and T cells. Its physiological role is to bind to lysophosphatidylcholine expressed on the surface of dead or dying cells (and some types of bacteria) in order to activate the complement system via C1q. CRP is synthesized by the liver in response to factors released by macrophages and fat cells (adipocytes). It is a member of the pentraxin family of proteins. It is not related to C-peptide (insulin) or protein C (blood coagulation). C-reactive protein was the first pattern recognition receptor (PRR) to be identified. History Discovered by Tillett and Francis in 1930, it was initially thought that CRP might be a pathogenic secretion since it was elevated in a variety of illnesses, including cancer. The later ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Complement System
The complement system, also known as complement cascade, is a part of the immune system that enhances (complements) the ability of antibodies and phagocytic cells to clear microbes and damaged cells from an organism, promote inflammation, and attack the pathogen's cell membrane. It is part of the innate immune system, which is not adaptable and does not change during an individual's lifetime. The complement system can, however, be recruited and brought into action by antibodies generated by the adaptive immune system. The complement system consists of a number of small proteins that are synthesized by the liver, and circulate in the blood as inactive precursors. When stimulated by one of several triggers, proteases in the system cleave specific proteins to release cytokines and initiate an amplifying cascade of further cleavages. The end result of this ''complement activation'' or ''complement fixation'' cascade is stimulation of phagocytes to clear foreign and damaged material ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Heparin
Heparin, also known as unfractionated heparin (UFH), is a medication and naturally occurring glycosaminoglycan. Since heparins depend on the activity of antithrombin, they are considered anticoagulants. Specifically it is also used in the treatment of heart attacks and unstable angina. It is given intravenously or by injection under the skin. Other uses for its anticoagulant properties include inside blood specimen test tubes and kidney dialysis machines. Common side effects include bleeding, pain at the injection site, and low blood platelets. Serious side effects include heparin-induced thrombocytopenia. Greater care is needed in those with poor kidney function. Heparin is contraindicated for suspected cases of vaccine-induced pro-thrombotic immune thrombocytopenia (VIPIT) secondary to SARS-CoV-2 vaccination, as heparin may further increase the risk of bleeding in an anti-PF4/heparin complex autoimmune manner, in favor of alternative anticoagulant medications (such as arg ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
