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Ferrichrome
Ferrichrome is a cyclic hexa-peptide that forms a complex with iron atoms. It is a siderophore composed of three glycine and three modified ornithine residues with hydroxamate groups N(OH)C(=O)C- The 6 oxygen atoms from the three hydroxamate groups bind Fe(III) in near perfect octahedral coordination. Ferrichrome was first isolated in 1952, and has been found to be produced by fungi of the genera ''Aspergillus'', ''Ustilago'', and ''Penicillium''. However, at the time there was no understanding regarding its involvement and contribution to iron transport. It was not until 1957 because of Joe Neilands work, where he first noted that Ferrichrome was able to act as an iron transport agent. Biological function Ferrichrome is a siderophore, which are metal chelating agents that have a low molecular mass and are produced by microorganisms and plants growing under low iron conditions. The main function of siderophores is to chelate ferric iron (Fe3+) from insoluble minerals from th ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ferrichrome A
Ferrichrome A is a siderophore in the ferrichrome family. Iron is an essential element for the survival and proliferation of organisms. Microorganisms produce and secrete potent iron chelators, also known as siderophores, to aid in the sequestration and increase bioavailability of iron. Since the discovery of ferrichrome in 1952, the ferrichrome family of siderophores contains at least 20 structurally distinct members of cyclic hexapeptides that chelate ferric iron via an octahedral coordination geometry through the oxygen atoms of the hydroxyl and the acyl groups of the three ornithine residues. Ferrichrome A was found as one of the two siderophores produced by the biotrophic basidiomycete ''Ustilago maydis'' during its saprotrophic growth phase. ''U. maydis'' is the causative agent of corn smut. Biosynthesis In ''U. maydis'', the ferrichrome A biosynthetic pathway begins with the HMG-CoA synthase (Hcs1) of acetyl-CoA and acetoacetyl-CoA for generation of Hydroxymethylglutaryl- ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Siderophore
Siderophores (Greek: "iron carrier") are small, high-affinity iron-chelating compounds that are secreted by microorganisms such as bacteria and fungi. They help the organism accumulate iron. Although a widening range of siderophore functions is now being appreciated. Siderophores are among the strongest (highest affinity) Fe3+ binding agents known. Phytosiderophores are siderophores produced by plants. Scarcity of soluble iron Despite being one of the most abundant elements in the Earth's crust, iron is not readily bioavailable. In most aerobic environments, such as the soil or sea, iron exists in the ferric (Fe3+) state, which tends to form insoluble rust-like solids. To be effective, nutrients must not only be available, they must be soluble. Microbes release siderophores to scavenge iron from these mineral phases by formation of soluble Fe3+ complexes that can be taken up by active transport mechanisms. Many siderophores are nonribosomal peptides, although several are biosynthes ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Siderophore
Siderophores (Greek: "iron carrier") are small, high-affinity iron-chelating compounds that are secreted by microorganisms such as bacteria and fungi. They help the organism accumulate iron. Although a widening range of siderophore functions is now being appreciated. Siderophores are among the strongest (highest affinity) Fe3+ binding agents known. Phytosiderophores are siderophores produced by plants. Scarcity of soluble iron Despite being one of the most abundant elements in the Earth's crust, iron is not readily bioavailable. In most aerobic environments, such as the soil or sea, iron exists in the ferric (Fe3+) state, which tends to form insoluble rust-like solids. To be effective, nutrients must not only be available, they must be soluble. Microbes release siderophores to scavenge iron from these mineral phases by formation of soluble Fe3+ complexes that can be taken up by active transport mechanisms. Many siderophores are nonribosomal peptides, although several are biosynthes ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Joe Neilands
John Brian "Joe" Neilands (September 11, 1921 – October 23, 2008) was a Canadian-born American biochemist and professor of biochemistry at the University of California, Berkeley, where he taught from 1951 until his retirement in 1993. Early life and education Neilands was born on September 11, 1921 in Glen Valley, British Columbia, to Thomas Abraham Neilands and Mary Rebecca Neilands (née Harpur), both of whom immigrated from Northern Ireland. He received his undergraduate degree from the University of Guelph in 1944, his master's degree from Dalhousie University in 1946, and his Ph.D. from the University of Wisconsin, Madison in biochemistry in 1949. He then completed a postdoctoral fellowship at the Karolinska Institutet's Medical Nobel Institute in Stockholm, Sweden. Career Neilands joined the faculty of the University of California, Berkeley in 1951 as an assistant professor, where he remained until he retired in 1993. In 1958, he was named a Guggenheim Fellow; during his ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Peptide
Peptides (, ) are short chains of amino acids linked by peptide bonds. Long chains of amino acids are called proteins. Chains of fewer than twenty amino acids are called oligopeptides, and include dipeptides, tripeptides, and tetrapeptides. A polypeptide is a longer, continuous, unbranched peptide chain. Hence, peptides fall under the broad chemical classes of biological polymers and oligomers, alongside nucleic acids, oligosaccharides, polysaccharides, and others. A polypeptide that contains more than approximately 50 amino acids is known as a protein. Proteins consist of one or more polypeptides arranged in a biologically functional way, often bound to ligands such as coenzymes and cofactors, or 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 pep ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Iron(III) Compounds
Iron () is a chemical element with symbol Fe (from la, ferrum) and atomic number 26. It is a metal that belongs to the first transition series and group 8 of the periodic table. It is, by mass, the most common element on Earth, right in front of oxygen (32.1% and 30.1%, respectively), forming much of Earth's outer and inner core. It is the fourth most common element in the Earth's crust. In its metallic state, iron is rare in the Earth's crust, limited mainly to deposition by meteorites. Iron ores, by contrast, are among the most abundant in the Earth's crust, although extracting usable metal from them requires kilns or furnaces capable of reaching or higher, about higher than that required to smelt copper. Humans started to master that process in Eurasia during the 2nd millennium BCE and the use of iron tools and weapons began to displace copper alloys, in some regions, only around 1200 BCE. That event is considered the transition from the Bronze Age to the Iron Age. In t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Lewis Acids And Bases
A Lewis acid (named for the American physical chemist Gilbert N. Lewis) is a chemical species that contains an empty orbital which is capable of accepting an electron pair from a Lewis base to form a Lewis adduct. A Lewis base, then, is any species that has a filled orbital containing an electron pair which is not involved in bonding but may form a dative bond with a Lewis acid to form a Lewis adduct. For example, NH3 is a Lewis base, because it can donate its lone pair of electrons. Trimethylborane (Me3B) is a Lewis acid as it is capable of accepting a lone pair. In a Lewis adduct, the Lewis acid and base share an electron pair furnished by the Lewis base, forming a dative bond. In the context of a specific chemical reaction between NH3 and Me3B, a lone pair from NH3 will form a dative bond with the empty orbital of Me3B to form an adduct NH3•BMe3. The terminology refers to the contributions of Gilbert N. Lewis. From p. 142: "We are inclined to think of substances as pos ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Rhodotorulic Acid
Rhodotorulic acid is the smallest of the 2,5-diketopiperazine family of hydroxamate siderophores which are high-affinity chelating agents for ferric iron, produced by bacterial and fungal phytopathogens for scavenging iron from the environment. It is a tetradentate ligand, meaning it binds one iron atom in four locations (two hydroxamate and two lactam moieties), and forms Fe2(siderophore)3 complexes to fulfill an octahedral coordination for iron. Rhodotorulic acid occurs in basidiomycetous yeasts and was found to retard the spore germination of the fungus ''Botrytis cinerea''. In combination with yeast ''R. glutinis'' it was found to be effective in the biocontrol of iprodione Iprodione is a hydantoin fungicide and nematicide. Application Iprodione is used on crops affected by Botrytis bunch rot, Brown rot, Sclerotinia and other fungal diseases in plants. It is currently applied in a variety of crops: fruit, vegetable ...-resistant ''B. cinerea'' of apple wounds caused by th ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Aerobactin
Aerobactin is a bacterial iron chelating agent (siderophore) found in ''E. coli''. It is a virulence factor enabling ''E. coli'' to sequester iron in iron-poor environments such as the urinary tract. Aerobactin is biosynthesized by the oxidation of lysine, catalyzed by the enzyme aerobactin synthase, which is then coupled to citric acid. The gene for this enzyme is found in the aerobactin operon, which is roughly 8 kilobases long and contains 5 or more genes in total. ''Yersinia pestis'' contains genes relating to aerobactin, but they have been inactivated by a frameshift mutation, thus ''Y. pestis'' is no longer able to synthesize aerobactin. Other homologs * Rhizobactin from ''Sinorhizobium'' * Alcaligin from ''Bordetella ''Bordetella'' () is a genus of small (0.2 – 0.7 µm), gram-negative coccobacilli of the phylum Pseudomonadota. ''Bordetella'' species, with the exception of '' B. petrii'', are obligate aerobes, as well as highly fastidious, or difficult ...'' ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Deferoxamine
Deferoxamine (DFOA), also known as desferrioxamine and sold under the brand name Desferal, is a medication that binds iron and aluminium. It is specifically used in iron overdose, hemochromatosis either due to multiple blood transfusions or an underlying genetic condition, and aluminium toxicity in people on dialysis. It is used by injection into a muscle, vein, or under the skin. Common side effects include pain at the site of injection, diarrhea, vomiting, fever, hearing loss, and eye problems. Severe allergic reactions including anaphylaxis and low blood pressure may occur. It is unclear if use during pregnancy or breastfeeding is safe for the baby. Deferoxamine is a siderophore from the bacteria ''Streptomyces pilosus''. Deferoxamine was approved for medical use in the United States in 1968. It is on the World Health Organization's List of Essential Medicines. Medical uses Deferoxamine is used to treat acute iron poisoning, especially in small children. This agent is al ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Enterobactin
Enterobactin (also known as enterochelin) is a high affinity siderophore that acquires iron for microbial systems. It is primarily found in Gram-negative bacteria, such as ''Escherichia coli'' and ''Salmonella typhimurium''. Enterobactin is the strongest siderophore known, binding to the ferric ion (Fe3+) with affinity K = 1052 M−1. This value is substantially larger than even some synthetic metal chelators, such as EDTA (Kf,Fe3+ ~ 1025 M−1). Due to its high affinity, enterobactin is capable of chelating even in environments where the concentration of ferric ion is held very low, such as within living organisms. Enterobactin can extract iron even from the air. Pathogenic bacteria can steal iron from other living organisms using this mechanism, even though the concentration of iron is kept extremely low due to the toxicity of free iron. Structure and biosynthesis Chorismic acid, an aromatic amino acid precursor, is converted to 2,3-dihydroxybenzoic acid (DHB) by a series of ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
