Yersinia pestis is a gram-negative, non-motile, coccobacillus bacterium without spores that is related to both Yersinia enterocolitica and Yersinia pseudotuberculosis, the pathogen from which Y. pestis evolved and responsible for the Far East scarlet-like fever. It is a facultative anaerobic organism that can infect humans via the Oriental rat flea. It causes the disease plague, which caused the Plague of Justinian and the Black Death, the deadliest pandemic in recorded history. Plague takes three main forms: pneumonic, septicemic, and bubonic. Yersinia pestis is a parasite of its host, the rat flea, which is also a parasite of rats, hence Y. pestis is a hyperparasite.
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.
Nonribosomal peptides (NRP) are a class of peptide secondary metabolites, usually produced by microorganisms like bacteria and fungi. Nonribosomal peptides are also found in higher organisms, such as nudibranchs, but are thought to be made by bacteria inside these organisms. While there exist a wide range of peptides that are not synthesized by ribosomes, the term nonribosomal peptide typically refers to a very specific set of these as discussed in this article.
Iron–sulfur proteins are proteins characterized by the presence of iron–sulfur clusters containing sulfide-linked di-, tri-, and tetrairon centers in variable oxidation states. Iron–sulfur clusters are found in a variety of metalloproteins, such as the ferredoxins, as well as NADH dehydrogenase, hydrogenases, coenzyme Q – cytochrome c reductase, succinate – coenzyme Q reductase and nitrogenase. Iron–sulfur clusters are best known for their role in the oxidation-reduction reactions of electron transport in mitochondria and chloroplasts. Both Complex I and Complex II of oxidative phosphorylation have multiple Fe–S clusters. They have many other functions including catalysis as illustrated by aconitase, generation of radicals as illustrated by SAM-dependent enzymes, and as sulfur donors in the biosynthesis of lipoic acid and biotin. Additionally, some Fe–S proteins regulate gene expression. Fe–S proteins are vulnerable to attack by biogenic nitric oxide, forming dinitrosyl iron complexes. In most Fe–S proteins, the terminal ligands on Fe are thiolate, but exceptions exist.
Yersinia pseudotuberculosis is a Gram-negative bacterium that causes Far East scarlet-like fever in humans, who occasionally get infected zoonotically, most often through the food-borne route. Animals are also infected by Y. pseudotuberculosis. The bacterium is urease positive.
In molecular biology, Beta-ketoacyl-ACP synthase EC 2.3.1.41, is an enzyme involved in fatty acid synthesis. It typically uses malonyl-CoA as a carbon source to elongate ACP-bound acyl species, resulting in the formation of ACP-bound β-ketoacyl species such as acetoacetyl-ACP.
Enterobactin 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.
Iron is an important biological element. It is used in both the ubiquitous iron-sulfur proteins and in vertebrates it is used in hemoglobin which is essential for blood and oxygen transport.
In enzymology, a ferric-chelate reductase (EC 1.16.1.7) is an enzyme that catalyzes the chemical reaction
Pathogenic bacteria are bacteria that can cause disease. This article focuses on the bacteria that are pathogenic to humans. Most species of bacteria are harmless and are often beneficial but others can cause infectious diseases. The number of these pathogenic species in humans is estimated to be fewer than a hundred. By contrast, several thousand species are part of the gut flora present in the digestive tract.
Aerobactin is a bacterial iron chelating agent (siderophore) found in E. coliand other Enterobacteriaceae species. It is a virulence factor enabling E. coli to sequester iron in iron-poor environments such as the urinary tract.
2,3-Dihydroxybenzoic acid is a natural phenol found in Phyllanthus acidus and in the aquatic fern Salvinia molesta. It is also abundant in the fruits of Flacourtia inermis. It is a dihydroxybenzoic acid, a type of organic compound.
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.
Ferroverdin refers to three different coordination compounds that were first isolated in 1955 by Chain, Tonolo, and Carilli. It consists of three p-vinylphenyl-3-nitroso-4-hydroxybenzoate ligands complexed with a ferrous ion. Ferroverdin is a green pigment produced in the mycelium of species of Streptomyces. It is claimed to be the “first stable ferrous compound to be found in nature.” There are three types of ferroverdin: A, B, and C. In ferroverdin A, both R groups are hydrogens. In ferroverdin B, R1 is a hydroxyl group (OH) and R2 is a hydrogen (according to a diagram in the paper, the R-groups are on the vinyl group, on the carbon opposite the phenyl; they are respectively trans and cis relative to the phenyl group). In ferroverdin C, R1 is a hydrogen while R2 is a carboxyl group (COOH). Ferroverdin is immune to chelating and oxidizing agents due to the strong interaction between the ligands and ferrous ion. However, it can be broken down by reductive processes.1 The presence of ferroverdin peaks when there are four to eight μg/mL of Fe2+ in the media usually in the form of a salt.
Many bacteria secrete small iron-binding molecules called siderophores, which bind strongly to ferric ions. FepA is an integral bacterial outer membrane porin protein that belongs to outer membrane receptor family and provides the active transport of iron bound by the siderophore enterobactin from the extracellular space, into the periplasm of Gram-negative bacteria. FepA has also been shown to transport vitamin B12, and colicins B and D as well. This protein belongs to family of ligand-gated protein channels.
Ferric-chelate reductase (NADPH) (EC 1.16.1.9, ferric chelate reductase, iron chelate reductase, NADPH:Fe3+-EDTA reductase, NADPH-dependent ferric reductase, yqjH (gene)) is an enzyme with systematic name Fe(II):NADP+ oxidoreductase. This enzyme catalyses the following chemical reaction
Ascorbate ferrireductase (transmembrane) (EC 1.16.5.1, cytochrome b561) is an enzyme with systematic name Fe(III):ascorbate oxidorectuctase (electron-translocating). This enzyme catalyses the following chemical reaction
Isochorismate pyruvate lyase is an enzyme responsible for catalyzing part of the pathway involved in the formation of salicylic acid. More specifically, IPL will use isochorismate as a substrate and convert it into salicylate and pyruvate. IPL is a PchB enzyme originating from the pchB gene in Pseudomonas aeruginosa.
Siderocalin(Scn), lipocalin-2, NGAL, 24p3 is a mammalian lipocalin-type protein that can prevent iron acquisition by pathogenic bacteria by binding siderophores, which are iron-binding chelators made by microorganisms. Iron serves as a key nutrient in host-pathogen interactions, and pathogens can acquire iron from the host organism via synthesis and release siderophores such as enterobactin. Siderocalin is a part of the mammalian defence mechanism and acts as an antibacterial agent. Crystallographic studies of Scn demonstrated that it includes a calyx, a ligand-binding domain that is lined with polar cationic groups. Central to the siderophore/siderocalin recognition mechanism are hybrid electrostatic/cation-pi interactions. To evade the host defences, pathogens evolved to produce structurally varied siderophores that would not be recognized by siderocalin, allowing the bacteria to acquire iron.
Petrobactin is a bis-catechol siderophore found in M. hydrocarbonoclasticus, A. macleodii, and the anthrax-producing B. anthracis. Like other siderophores petrobactin is a highly specific iron(III) transport ligand, contributing to the marine microbial uptake of environmental iron.
