Lyngbyatoxin-a is a type of alkaloid

cyanotoxin Cyanotoxins are toxins produced by cyanobacteria (also known as blue-green algae). Cyanobacteria are found almost everywhere, but particularly in lakes and in the ocean where, under high concentration of phosphorus conditions, they reproduce exp ...

produced by certain

cyanobacteria Cyanobacteria ( ) are a group of autotrophic gram-negative bacteria that can obtain biological energy via oxygenic photosynthesis. The name "cyanobacteria" () refers to their bluish green (cyan) color, which forms the basis of cyanobacteri ...

species, most notably '' Moorea producens'' (formerly classified as ''

Lyngbya ''Lyngbya'' is a genus of cyanobacteria, unicellular autotrophs that form the basis of the oceanic food chain. As a result of recent genetic analyses, several new genera were erected from this genus: ''e.g.'', '' Moorea'', '' Limnoraphis'', '' O ...

majuscula''). It is produced as defense mechanism to ward off any would-be predators of the bacterium, being a potent

blister agent A blister agent (or vesicant) is a chemical compound that causes severe skin, eye and mucosal pain and irritation in the form of severe chemical burns resulting in fluid filled blisters. Named for their ability to cause vesication, blister a ...

as well as

carcinogen A carcinogen () is any agent that promotes the development of cancer. Carcinogens can include synthetic chemicals, naturally occurring substances, physical agents such as ionizing and non-ionizing radiation, and biologic agents such as viruse ...

. Low concentrations cause a common skin condition known as

seaweed dermatitis ''Lyngbya majuscula'' is a species of filamentous cyanobacteria in the genus '' Lyngbya''. It is named after the Dane Hans Christian Lyngbye. As a result of recent genetic analyses, several new genera were erected from the genus ''Lyngbya'': ...

Biosynthesis

Lyngbyatoxin is a

terpenoid The terpenoids, also known as isoprenoids, are a class of naturally occurring organic compound, organic chemicals derived from the 5-carbon compound isoprene and its derivatives called terpenes, diterpenes, etc. While sometimes used interchangeabl ...

indole alkaloid Indole alkaloids are a class of alkaloids containing a structural moiety of indole; many indole alkaloids also include isoprene groups and are thus called terpene indole or secologanin tryptamine alkaloids. Containing more than 4100 known differ ...

hybrid that belongs to the class of non-ribosomal peptides (NRPs). Lyngbyatoxin contains a nucleophilic indole ring that takes part in the activation of protein kinases. Figure 1, shows the biosynthesis of Lyngbyatoxin reported by Neilan et al. and Gerwick et al. The non-ribosomal peptide synthase (NRPS) LtxA protein condenses L-methyl-valine and L-tryptophan to form the linear dipeptide N-methyl-L-valyl-L-tryptophan. The latter is released via a NADPH-dependent reductive cleavage to form the aldehyde which is subsequently reduced to the corresponding alcohol. A P450-dependent monooxygenase called LtxB then performs the oxidation and subsequent cyclization of N-methyl-L-valyl-L-tryptophan. Finally, LtxC transfers a

geranyl Geraniol is a monoterpenoid and an alcohol. It is the primary component of citronella oil and is a primary component of rose oil and palmarosa oil. It is a colorless oil, although commercial samples can appear yellow. It has low solubility in w ...

functional group In organic chemistry, a functional group is any substituent or moiety (chemistry), moiety in a molecule that causes the molecule's characteristic chemical reactions. The same functional group will undergo the same or similar chemical reactions r ...

from

geranyl pyrophosphate Geranyl pyrophosphate (GPP), also known as geranyl diphosphate (GDP), is the pyrophosphate ester of the terpenoid geraniol. Its salts are colorless. It is a precursor to many thousands of natural product, natural products. Occurrence GPP is an int ...

(GPP) to carbon number 7 of the indole ring.

References

{{Cyanotoxins Indole alkaloids Cyanotoxins Blister agents Bacterial alkaloids