Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
5
pubmed:dateCreated
2005-1-25
pubmed:databankReference
pubmed:abstractText
We reported previously that the Rhodococcus erythropolis strain AN12 synthesizes the monocyclic carotenoids 4-keto gamma-carotene and gamma-carotene. We also identified a novel lycopene beta-monocyclase in this strain. Here we report the identification of the rest of the carotenoid synthesis genes in AN12. Two of these showed apparent homology to putative phytoene dehydrogenases. Analysis of Rhodococcus knockout mutants suggested that one of them ( crtI) encodes a phytoene dehydrogenase, whereas the other ( crtO) encodes a beta-carotene ketolase. Expression of the beta-carotene ketolase gene in an Escherichia coli strain which accumulates beta-carotene resulted in the production of canthaxanthin. In vitro assays using a crude extract of the E. coli strain expressing the crtO gene confirmed its ketolase activity. A crtO homologue (DR0093) from Deinococcus radiodurans R1 was also shown to encode a beta-carotene ketolase, despite its sequence homology to phytoene dehydrogenases. The Rhodococcus and Deinococcus CrtO ketolases both catalyze the symmetric addition of two keto groups to beta-carotene to produce canthaxanthin. Even though this activity is similar to the CrtW-type of ketolase activity, the CrtO ketolases show no significant sequence homology to CrtW-type ketolases. The presence of six conserved regions may be a signature for the CrtO-type of beta-carotene ketolases.
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Dec
pubmed:issn
1617-4615
pubmed:author
pubmed:issnType
Print
pubmed:volume
272
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
530-7
pubmed:dateRevised
2007-8-21
pubmed:meshHeading
pubmed-meshheading:15538629-Amino Acid Sequence, pubmed-meshheading:15538629-Bacterial Proteins, pubmed-meshheading:15538629-Base Sequence, pubmed-meshheading:15538629-Canthaxanthin, pubmed-meshheading:15538629-Carotenoids, pubmed-meshheading:15538629-Chromatography, High Pressure Liquid, pubmed-meshheading:15538629-Chromatography, Liquid, pubmed-meshheading:15538629-Cloning, Molecular, pubmed-meshheading:15538629-Cluster Analysis, pubmed-meshheading:15538629-DNA Primers, pubmed-meshheading:15538629-Deinococcus, pubmed-meshheading:15538629-Escherichia coli, pubmed-meshheading:15538629-Gene Expression, pubmed-meshheading:15538629-Mass Spectrometry, pubmed-meshheading:15538629-Molecular Sequence Data, pubmed-meshheading:15538629-Oxygenases, pubmed-meshheading:15538629-Phylogeny, pubmed-meshheading:15538629-Rhodococcus, pubmed-meshheading:15538629-Sequence Alignment, pubmed-meshheading:15538629-Sequence Analysis, DNA
pubmed:year
2004
pubmed:articleTitle
Novel beta-carotene ketolases from non-photosynthetic bacteria for canthaxanthin synthesis.
pubmed:affiliation
Biological and Chemical Sciences and Engineering, Central Research and Development, Experimental Station, E328/B48, E. I. DuPont de Nemours Inc., Wilmington, DE 19880-0328, USA.
pubmed:publicationType
Journal Article, Comparative Study