원문정보
초록
영어
In vivo color complementation screen utilizing carotenoid biosynthetic pathway enzymes was
developed and applied for screening C25 farnesylgeranyl diphosphate (FGDP) synthase mutants.
The 12 mutant clones of a C20 GGDP synthase activity were isolated with the color
complementation screening. Analysis of these mutants revealed that C25 FGDP synthase controls
chain length specificity in three different ways. Two mutants have a single mutation at the 8th
amino acid upstream of a conserved first aspartate rich motif (FARM), which is well-known for
chain elongation reaction of all prenyl diphosphate synthases. One mutant carries a single mutation at the 7th amino acid upstream of another conserved region (-GQ-), which was recently found to be another important region controlling chain elongation of a type III C20 GGDP synthase and E. coli C15 FDP synthase. Finally one mutant carrying four mutations showed a distinguished mechanism for chain length determination. The molecular modeling, site-directed mutagenesis and in vitro assay of it suggest that the product chain specificity can be also controlled by structural change provoked by amino acids cooperatively.