Functional assignment of Erwinia herbicola Eho10 carotenoid genes expressed in Escherichia coli.
Erwinia herbicola is a nonphotosynthetic bacterium that is yellow pigmented due to the presence of carotenoids. When the Erwinia carotenoid biosynthetic genes are expressed in Escherichia coli, this bacterium also displays a yellow phenotype. The DNA sequence of the plasmid pPL376, carrying the entire Erwinia carotenoid gene cluster, has been found to contain 12 open reading frames (ORFs). Six of the ORFs have been identified as carotenoid biosynthesis genes that code for all the enzymes required for conversion of farnesyl pyrophosphate (FPP) to zeaxanthin diglucoside via geranylgeranyl pyrophosphate, phytoene, lycopene, beta-carotene, and zeaxanthin. These enzymatic steps were assigned after disruption of each ORF by a specific mutation and analysis of the accumulated intermediates. Carotenoid intermediates were identified by the absorption spectra of the colored components and by high pressure liquid chromatographic analysis. The six carotenoid genes are arranged in at least two operons. The gene coding for beta-carotene hydroxylase is transcribed in the opposite direction from that of the other carotenoid genes and overlaps with the gene for phytoene synthase.
Hundle
B
B
Department of Chemistry, University of California, Berkeley 94720.
Alberti
M
M
Nievelstein
V
V
Beyer
P
P
Kleinig
H
H
Armstrong
G A
GA
Burke
D H
DH
Hearst
J E
JE
D019883:Alkyl and Aryl Transferases; D000595:Amino Acid Sequence; D001426:Bacterial Proteins / Q000235:genetics; D001483:Base Sequence; D019757:Carbon-Oxygen Lyases; D002338:Carotenoids / Q000096:biosynthesis* / Q000235:genetics*; D004885:Erwinia / Q000201:enzymology / Q000235:genetics*; D005798:Genes, Bacterial; D051232:Geranylgeranyl-Diphosphate Geranylgeranyltransferase; D005964:Glucosyltransferases / Q000235:genetics; D007168:IMP Dehydrogenase / Q000235:genetics; D019753:Intramolecular Lyases; D007535:Isomerases / Q000235:genetics; D008190:Lyases / Q000235:genetics; D026901:Membrane Transport Proteins / Q000235:genetics; D006899:Mixed Function Oxygenases / Q000235:genetics; D008969:Molecular Sequence Data; D016297:Mutagenesis, Site-Directed; D016366:Open Reading Frames; D009876:Operon; D010088:Oxidoreductases / Q000235:genetics; D010858:Pigmentation / Q000235:genetics; D010957:Plasmids; D015183:Restriction Mapping; D017386:Sequence Homology, Amino Acid; D027981:Symporters; D014166:Transferases / Q000235:genetics
D001426:Bacterial Proteins; D026901:Membrane Transport Proteins; D027981:Symporters; D002338:Carotenoids; C021548:melibiose permease; D006899:Mixed Function Oxygenases; D010088:Oxidoreductases; D007168:IMP Dehydrogenase; C079232:beta-carotene hydroxylase; C022398:phytoene dehydrogenase; D014166:Transferases; D005964:Glucosyltransferases; C077175:zeaxanthin glucosyltransferase; D019883:Alkyl and Aryl Transferases; D051232:Geranylgeranyl-Diphosphate Geranylgeranyltransferase; C022696:O-succinylhomoserine (thiol)-lyase; D008190:Lyases; D019757:Carbon-Oxygen Lyases; D007535:Isomerases; D019753:Intramolecular Lyases; C070925:lycopene cyclase-isomerase