<jats:title>Abstract</jats:title><jats:p><jats:bold>Combinatorial biosynthesis meets combinatorial pharmacology, cyanobacterial style</jats:bold>: A new antimitotic natural product with features of both dolastatins 10 and 15 was isolated from the same Floridian <jats:italic>Symploca</jats:italic> sp. sample that produced the histone deacetylase inhibitor largazole. Both agents in combination are more effective in inhibiting cancer cell proliferation than either agent alone.<jats:boxed-text content-type="graphic" position="anchor"><jats:graphic xmlns:xlink="http://www.w3.org/1999/xlink" mimetype="image/gif" position="anchor" specific-use="enlarged-web-image" xlink:href="graphic/mcontent.gif"><jats:alt-text>magnified image</jats:alt-text></jats:graphic></jats:boxed-text>