Open AccessNew functional assignment of the carotenogenic genes crtB and crtE with constructs of these genes from Erwinia species
Author(s) -
Sandmann Gerhard,
Misawa Norihiko
Publication year - 1992
Publication title -
fems microbiology letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.899
H-Index - 151
eISSN - 1574-6968
pISSN - 0378-1097
DOI - 10.1111/j.1574-6968.1992.tb05162.x
Subject(s) - phytoene synthase , biology , geranylgeranyl pyrophosphate , gene , phytoene , agrobacterium tumefaciens , escherichia coli , phytoene desaturase , biochemistry , genetics , enzyme , transformation (genetics) , gene expression , biosynthesis , prenylation
The role of carotenoid genes crtB and crtE has been functionally assigned. These genes were cloned from Erwinia into Escherichia coli or Agrobacterium tumefaciens . Their functions were elucidated by assaying early isoprenoid enzymes involved in phytoene formation. In vitro reactions from extracts of E. coli carrying the crtE gene or a complete carotenogenic gene cluster in which crtB was deleted showed an elevated conversion of farnesyl pyrophosphate (FPP) into geranylgeranyl pyrophosphate (GGPP). These results strongly indicate that the crtE gene encodes GGPP synthase. Introduction of the crtB gene into A. tumefaciens led to the conversion of GGPP into phytoene. This activity was absent in similar transformants with the crtE gene. Thus, the crtB probably encodes phytoene synthase, which was further supported by demonstration that phytoene accumulated in E. coli harboring both the crtB genes.