A likely biogenetic gateway linking 2-aminoimidazolinone metabolites of sponges to proline: spontaneous oxidative conversion of the pyrrole-proline-guanidine pseudo-peptide to dispacamide A.
A new spontaneous oxidative transformation of the associated pyrrole-proline-guanidine to the natural marine pyrrole 2-aminoimidazolinone derivative has been achieved. The sensitive reaction requires air oxygen and the N-acylation of proline by pyrrole-2-carboxylic acid. Proline metabolism and pyrrole 2-aminoimidazole secondary metabolites formation seem to be related and are utilized by sponges under stress conditions for their defense against predators. A plausible stress-induced oxidative chemical pathway that establishes dispacamide derivatives as the forerunners in the biogenetic synthesis of the key pyrrole 2-aminoimidazole oroidin is proposed. The mechanism of the reaction seems to be another development of the known luciferins' chemiluminescent reactions in bioluminescent marine organisms.
Institut de Chimie des Substances Naturelles du CNRS, BP 1, 91198 Gif-sur-Yvette, France.
Nathalie
N
Travert
Ali
A
Al-Mourabit
D000586:Amination; D000818:Animals; D040761:Biomimetic Materials / Q000737:chemistry; D019791:Guanidine / Q000031:analogs & derivatives*; D007093:Imidazoles / Q000138:chemical synthesis / Q000737:chemistry*; D010084:Oxidation-Reduction; D010455:Peptides / Q000737:chemistry*; D011161:Porifera / Q000378:metabolism*; D011392:Proline / Q000031:analogs & derivatives* / Q000737:chemistry; D011758:Pyrroles / Q000737:chemistry*
D007093:Imidazoles; D010455:Peptides; D011758:Pyrroles; C002986:2-pyrrolecarboxylic acid; C014973:2-aminoimidazole; D011392:Proline; D019791:Guanidine