   2.5.1.129 | dimethylallyl phosphate + FMNH2 = prenylated FMNH2 + phosphate |
the prenyltransferase mechanism of UbiX resembles that of the terpene synthases. The active site environment is dominated by Pi systems, which assist phosphate-C1' bond breakage following FMN reduction, leading to formation of the N5-C19 bond. UbiX then acts as a chaperone for adduct reorientation, via transient carbocation species, leading ultimately to formation of the dimethylallyl C39-C6 bond, reaction mechanism, overvie. Stopped-flow experiments mixing reduced FMNH2-UbiX with dimethylallyl phosphate under anaerobic conditions reveal transient formation of a distinct spectral species before formation of the prFMNreduced product. The dimethylallyl phosphate substrate is located directly above the FMN isoalloxazine re face, with the dimethylallyl moiety sandwiched between the FMN and A89-S90. The dimethylallyl group is furthermore surrounded by aromatic ring systems of W84, Y169 and W200 that, together with the FMN dimethylbenzene moiety, resemble the Pi-cage found in other prenyltransferases or terpene synthases |
-, 734780 |
