Isoprenoids Are Essential for Fruiting Body Formation in

It was recently shown thatMyxococcus xanthus harbors an alternative and reversible biosynthetic pathway to isovaleryl coenzyme A (CoA) branching from 3-hydroxy-3-methylglutaryl-CoA. Analyses of various mutants in these pathways for fatty acid profiles and fruiting body formation revealed for the first time the importance of isoprenoids for myxobacterial development. Myxobacteria are unique among the prokaryotes as (i) they can form highly complex fruiting bodies under starvation con-ditions, even up to microscopic tree-like structures (28); (ii) they can move on solid surfaces using different motility mech-anisms (16); (iii) they produce some of the most cytotoxic secondary metabolites, with epothilone already in clinical use against cancer (2, 3); and (iv) they harbor the largest prokary-otic genomes found so far (15, 27). The large genome might be directly related to their complex life-style and the diverse sec-ondary (3) and primary (9) metabolisms. Already in 2002 we found that myxobacteria are able to produce isovaleryl coen