Lipomannan
Lipomannan is a mycobacterium immune agonist.[1] In addition, it is a major constituent of the mycobacterium cell wall. This gycloconjugate is a virulence factor that plays a key role in the human immune system via interaction with various immune cells. It is also considered to be a precursor of lipoarabinomannans.
It is a trigger for TLR 2.
It consists of an α-linked mannan, which consists of 50-70 residues, with some branches points linked glycosidically to a diglyceride of which the fatty acids are similar to those of the whole cell lipid. In addition, succinic acid residues are present as O-acyl substituents on about one in four of the mannose residues, the terminal carboxyl group of the succinic acid providing the whole polymer with a considerable number of acidic functions.
Lipomannan has functional components that resemble lipoteichoic acids; a lipophilic region and a hydrophilic portion with frequent acid groups.
Lipomannan is a phosphorylated polysaccharide associated with the cell enelop and is considered to be the multimannosylated form of PIM which is primariy located in the plasma membrane. Structurally, LM is composed of two segments: a PI anchor to which is attached an α-D-mannan domain; both play key roles in inducing cytokine production by phagocytic cells. Mannose core ocnsists of a linear α(1-6)-linked mannan backbone extending from the c-6 of the myo-inositol; the mannan chains is further substituted by α-(1-2) man-p side branches.
References
- ↑ Doz E, Rose S, Nigou J, et al. (2007). "Acylation determines the TLR-dependent positive versus TLR2-, mannose receptor- and SIGNR1-independent negative regulation of proinflammatory cytokines by mycobacterial lipomannan". The Journal of Biological Chemistry. 282 (36): 26014–26025. doi:10.1074/jbc.M702690200. PMID 17617634.
External links
- Lipomannan at the US National Library of Medicine Medical Subject Headings (MeSH)