Brunsvicamides A-C: sponge-related cyanobacterial peptides with Mycobacterium tuberculosis protein tyrosine phosphatase inhibitory activity.
Müller D, Krick A, Kehraus S, Mehner C, Hart M, Küpper FC, Saxena K, Prinz H, Schwalbe H, Janning P, Waldmann H, König GM.
The cyanobacterium Tychonema sp. produces the new cyclic hexapeptides brunsvicamide A-C (1-3). Brunsvicamide B (2) and C (3) selectively inhibit the Mycobacterium tuberculosis protein tyrosine phosphatase B (MptpB), a potential drug target for tuberculosis therapy for which no inhibitors are known to date. Brunsvicamide C contains an N-methylated N'-formylkynurenine moiety, a unique structural motif in cyclic peptides. The new peptides are related to the sponge-derived mozamides, supporting the suggestion that secondary metabolites of certain marine invertebrates are produced by associated microorganisms. Thus, microorganisms phylogenetically related to symbionts of marine invertebrates can be judged as a means to supply 'marine-like' compounds for drug development.