FIG. 6.

GC-MS analysis of oxidized sesquiterpenes produced from germacrene A by Nostoc sp. P450. Culture supernatant of E. coli cells coexpressing single-domain sesquiterpene synthase NS1 and P450NS from Nostoc sp. along with the ferredoxin/ferredoxin:NADPH reductase system from Nostoc sp. were analyzed for the accumulation of new oxygenated sesquiterpenes. Three new peaks (labeled 1 to 3; top trace), each with a molecular ion of an m/z of 220, appeared in the chromatogram compared to control cells (bottom trace) that coexpress only terpene synthase NS1 and reductase proteins. β-Elemene (the rearrangement product of germacrene A) present in the supernatant of the control culture is not present in the culture expressing terpene synthase and P450. Mass spectra for the two larger peaks are shown and suggest the addition of one hydroxyl group to germacrene A.