As a result of the IIMENA project, we now report the discovery of gargantulides B and C, which are among the largest and most complex bacterial polyketides discovered so far.
These huge macrolactones were isolated from an Amycolatopsis sp. strain during an antibacterial screening campaign and their structures were fully elucidated based on 2D NMR spectroscopy. Subsequent identification and analysis of their extraordinarily large biosynthetic gene cluster, together with extensive NMR-based analyses, allowed us to completely assign and revise the absolute stereochemistry of the entire gargantulide family.
The new macrolides showed potent antibacterial activity against Gram-positive bacteria including methicillin-resistant Staphylococcus aureus (MRSA) and vancomycin-resistant Enterococcus (VRE), and moderate but unusual activity against the clinically relevant Gram-negative pathogen Acinetobacter baumannii.
If you want to know more about these interesting bioactive compounds and their biosynthesis, please have a look at Organic Chemistry Frontiers:
To learn more about the whole genome of the producing strain, see also this paper