Coexpression of Spo9 and Fps1 is required for GGPS activity. E. coli DH10B carrying pACCAR25ΔcrtE was transformed with pMAL-c, pMAL(BTS1), pMAL(spo9), pMAL(fps1), pMAL (spo9+fps1), pMAL(spo9-R109Q+fps1), pMAL(spo9+fps1-R104Q), or pMAL(spo9-R109Q+fps1-R104Q); plated on LB medium supplemented with ampicillin and chloramphenicol; and incubated at 28°C for 3 d.