Siderocalin
Encyclopedia
Siderocalin is a protein
that is produced by the body in response to bacterial infection. During an infection, bacteria produce iron-chelators called siderophores, which are used for 'stealing' iron from the host. E. coli
, for example, produces a catecholate type of siderophore called Enterobactin
(also known as enterochelin) that binds iron(III) strongly (the binding constant K is approximately 1052 M−1). Siderocalin has been shown to bind ferric-catecholates, one of which is enterobactin and hence prevents the iron from being delivered to the bacteria. It thus can be seen as part of an innate immune response for protection against infection.
(NGAL) or human neutrophil lipocalin) is part of a family of proteins known as lipocalins, which are small extracellular proteins that bind to small (usually hydrophobic) molecules. Many lipocalins bind to retinol (also known as vitamin A) and are involved in the transport of retinol. It is only in recent years that NGAL has been recognised as a scavenger of siderophores. This discovery resulted in its new name siderocalin (sidero for siderophore, calin for lipocalin).
Protein
Proteins are biochemical compounds consisting of one or more polypeptides typically folded into a globular or fibrous form, facilitating a biological function. A polypeptide is a single linear polymer chain of amino acids bonded together by peptide bonds between the carboxyl and amino groups of...
that is produced by the body in response to bacterial infection. During an infection, bacteria produce iron-chelators called siderophores, which are used for 'stealing' iron from the host. E. coli
Escherichia coli
Escherichia coli is a Gram-negative, rod-shaped bacterium that is commonly found in the lower intestine of warm-blooded organisms . Most E. coli strains are harmless, but some serotypes can cause serious food poisoning in humans, and are occasionally responsible for product recalls...
, for example, produces a catecholate type of siderophore called Enterobactin
Enterobactin
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....
(also known as enterochelin) that binds iron(III) strongly (the binding constant K is approximately 1052 M−1). Siderocalin has been shown to bind ferric-catecholates, one of which is enterobactin and hence prevents the iron from being delivered to the bacteria. It thus can be seen as part of an innate immune response for protection against infection.
Origin
Siderocalin (also known as neutrophil gelatinase-associated lipocalinLipocalin
The lipocalins are a family of proteins which transport small hydrophobic molecules such as steroids, bilins, retinoids, and lipids. They share limited regions of sequence homology and a common tertiary structure architecture...
(NGAL) or human neutrophil lipocalin) is part of a family of proteins known as lipocalins, which are small extracellular proteins that bind to small (usually hydrophobic) molecules. Many lipocalins bind to retinol (also known as vitamin A) and are involved in the transport of retinol. It is only in recent years that NGAL has been recognised as a scavenger of siderophores. This discovery resulted in its new name siderocalin (sidero for siderophore, calin for lipocalin).