Tambjamine

Tambjamines are a group of natural products that are structurally related to prodiginines and are characterized by a 4-methoxy-2,2'-bipyrrolenamine structure.  Tambjamines are composed of two pyrrole rings with an enamine moiety at C-5 and a methoxy group at C-4, and the majority have short alkyl chains substituted for the enamine nitrogen.  This group of alkaloids have been isolated from marine invertebrates and bacteria (both marine and terrestrial). 

Marine sources and ecological roles 
The large nudibranch Roboastra tigris is a known predator of Tambje eliora and Tambje abdere, two species of smaller nudibranchs.  The chemical extracts of all three nudibranch species contain tambjamines, which were traced to Sessibugula translucens, a food source of the two prey species.  It is hypothesized that tambjamines are a chemical defense mechanism of the bryozoan against feeding by the spotted kelpfish Gibbonsia elegans. 

Biosynthesis 

The biosynthetic gene cluster responsible for tambjamine production was identified in 2007 using functional genomic analysis of a Pseudoalteromonas tunicata strain.  The Tam cluster consists of 19 proteins, 12 of which were found to be highly similar to proteins in the Red and Pig pathways based on sequence data.  The proposed biosynthesis of tambjamine YP1 involves the incorporation of proline, malonyl Co-A, and serine in the synthesis of MBC. 

AfaA is hypothesized to activate long-chain fatty acids while the predicted dehydrogenase, TamT, introduces a double bond into a fatty acyl side chain.  It is presumed that TamH then carries out the reduction of the CoA-ester to form an aldehyde intermediate, followed by transamination.  Condensation of the dodec-3-en-1-amine product of this reaction and MBC by TamQ, results in the tambjamine YP1. 

References 

Category:Alkaloids
Category:Enamines
Category:Ethers
Category:Pyrroles