Marine bacteria. XXXV. Bromoalterochromides A and A ', unprecedented chromopeptides from a marine Pseudoalteromonas maricaloris strain KMM 636

The marine strain Pseudoalteromonas maricaloris KMM 636(T) was found to produce an inseparable mixture of two brominated yellow main pigments, bromoalterochromide A and A', in a ratio of 3:1. Both pigments are Thr-Val-Asn-Asn-X pentapeptide lactones, where the amino group of Thr is acylated with 9-(3-bromo-4-hydroxyphenyl)-nona-2,4,6,8-tetraenoic acid, and X is alle and Leu, respectively. They possess cytotoxic effects on developing eggs of the sea urchin Strongylocentrotus intermedius, but no antibiotic activity.