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Cloning and expression in Escherichia coli of the gene encoding β‐C‐4‐oxygenase, that converts β‐carotene to the ketocarotenoid canthaxanthin in Haematococcus pluvialis
Author(s) -
Tamar Lotan,
Joseph Hirschberg
Publication year - 1995
Publication title -
febs letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.593
H-Index - 257
eISSN - 1873-3468
pISSN - 0014-5793
DOI - 10.1016/0014-5793(95)00368-j
Subject(s) - canthaxanthin , astaxanthin , haematococcus pluvialis , biochemistry , biology , carotenoid , escherichia coli , chemistry , microbiology and biotechnology , gene
In the green alga Haematococcus pluvialis the ketocarotenoid astaxanthin accumulates under stress conditions. Astaxanthin is a red carotenoid pigment which possess antioxidative activity. We have cloned the gene for β‐C‐4 oxygenase (β‐carotene ketolase) from the green algae H. pluvialis . The cloning method took advantage of a strain of E. coli which was genetically engineered to produce β‐carotene. An expression cDNA library of H. pluvialis was transfected to cells of this strain and visually screened for brown‐red pigmented colonies. One colony out of 100,000 transformants showed color change due to accumulation of canthaxanthin. The cDNA clone in this transformant colony encodes the enzyme β‐C‐4 oxygenase that catalyzes the conversion of β carotene to canthaxanthin via echinenone. This enzyme does not convert zeaxanthin to astaxanthin. It is concluded that in H. pluvialis astaxanthin is synthesized via canthaxanthin and therefore an additional enzyme is predicted, which converts canthaxanthin to astaxanthin.