Molecular modeling of 5-desacetylaltohyrtin A, a spongean cytotoxic macrolide

The solution structure of 5-desacetylaltohyrtin A, an extremely cytotoxic macrolide isolated from a marine sponge, was analyzed by NMR and restrained molecular dynamics. The average value of pairwise RMSD for the backbone (from C1 to C43) of the 10 lowest energy structures was 0.50±0.22 Å. The stereostructure of C14–C16 in 5-desacetylaltohyrtin A was further verified by restrained molecular dynamic calculation using incorrect chiral restraints.