Balskus, EmilyWalsh, Christopher2014-05-092009Balskus, Emily P., and Christopher T. Walsh. 2009. “ An Enzymatic Cyclopentyl[ b ]indole Formation Involved in Scytonemin Biosynthesis .” Journal of the American Chemical Society 131 (41) (October 21): 14648–14649.0002-78631520-5126http://nrs.harvard.edu/urn-3:HUL.InstRepos:12168179Previous studies of the biosynthetic enzymes involved in the assembly of scytonemin (1), a cyanobacterial sunscreen, have identified β-ketoacid 2 as an important intermediate that is produced by ThDP-dependent enzyme ScyA. We now report that ScyC, previously annotated as a hypothetical protein, catalyzes cyclization and decarboxylation of 2 to generate ketone 5. Assembly of the cyclopentyl[b]indole structure in this manner has little precedent in the chemical literature. Additional mechanistic experiments have revealed that cyclization likely precedes decarboxylation and that the latter event may provide a driving force for cyclopentane formation.en-USJournal Article2014-05-0910.1021/ja906752u