Chemistry: molecular biology and microbiology – Micro-organism – tissue cell culture or enzyme using process... – Preparing oxygen-containing organic compound
Reexamination Certificate
2001-07-23
2003-04-22
Saidha, Tekchand (Department: 1652)
Chemistry: molecular biology and microbiology
Micro-organism, tissue cell culture or enzyme using process...
Preparing oxygen-containing organic compound
C435S067000, C435S189000, C435S252300, C435S320100, C435S410000, C435S822000, C435S946000, C536S023200
Reexamination Certificate
active
06551807
ABSTRACT:
BACKGROUND OF THE INVENTION
Carotenoids are widely distributed natural pigments that are responsible for many of the yellow, orange and red colors seen in living organisms. They have important commercial uses as coloring agents in the food industry, as feed and food additives, in cosmetics and as provitamin A precursors.
The plant species
Adonis aestivalis
produces flowers with petals that are deep red in color and nearly black at the base of the petals due to the accumulation of ketocarotenoid and other carotenoid pigments (Neamtu et al.,
Rev. Roum. Biochim
. 6:157, 1969). This pattern of carotenoid accumulation accounts for the common name of some varieties of this species: summer pheasant's eye.
Among the carotenoids identified in the petals of the red petal varieties of these various species is the ketocarotenoid astaxanthin (3,3′-dihydroxy-4,4′-diketo-b,b-carotene; see FIG.
1
). Various other ketocarotenoids (see
FIG. 1
) including 3-hydroxyechinenone (3-hydroxy-4-keto-b,b-carotene),adonirubin (3-hydroxy-4,4′-diketo-b,b-carotene) adonixanthin (3,3′-dihydroxy-4-keto-b,b-carotene) and isozeaxanthin (4,4′-dihydroxy-b,b-carotene; see T. W. Goodwin, The Biochemistry of the Carotenoids, vol I. Plants, 2nd edition, 1980, page 147) have also been reported. The latter compound is consistent with speculation that the 4-hydroxy may be an intermediate in the formation of the 4-keto group.
SUMMARY OF THE INVENTION
There is appreciable interest in the biological production of carotenoids, in particular the orange-colored ketocarotenoids such as astaxanthin and canthaxanthin (FIG.
1
), and in the modification of carotenoid composition. For this reason, an
A. aestivalis
flower cDNA library was constructed and screened for cDNAs encoding enzymes (hereinafter referred to as “ketolases” although the specific biochemical activity has not yet been established) involved in the conversion of b-carotene into orange compounds with absorption properties similar to those exhibited by common ketocarotenoids such as canthaxanthin (FIG.
1
). Two distinctly different
Adonis aestivalis
cDNAs were obtained from among a number of cDNAs that were selected on this basis.
Thus, a first aspect of the present invention is a purified nucleic acid sequence which encodes for a protein having ketolase enzyme activity and has the nucleic acid sequence of SEQ ID NO: 1 or 3.
The invention also includes a purified nucleic acid sequence which encodes for a protein having ketolase enzyme activity and having the amino acid sequence of SEQ ID NO: 2 or 4.
The invention also includes vectors which comprise any portion of the nucleic acid sequences listed above, and host cells transformed with such vectors.
Another aspect of the present invention is a method of producing a ketocarotenoid in a host cell, the method comprising
inserting into the host cell a vector comprising a heterologous nucleic acid sequence which encodes for a protein having ketolase enzyme activity and comprises (1) SEQ ID NO: 1 or 3 or (2) a sequence which encodes the amino acid sequence of SEQ ID NO: 2 or 4, wherein the heterologous nucleic acid sequence is operably linked to a promoter; and
expressing the heterologous nucleic acid sequence, thereby producing the ketolase enzyme.
Another subject of the present invention is a method of modifying the production of carotenoids in a host cell, relative to an untransformed host cell, the method comprising
inserting into a host cell which already produces carotenoids a vector comprising a heterologous nucleic acid sequence which encodes for a protein having ketolase enzyme activity and comprises (1) SEQ ID NO: 1 or 3 or (2) a sequence which encodes the amino acid sequence of SEQ ID NO: 2 or 4, wherein the heterologous nucleic acid sequence is operably linked to a promoter; and
expressing the heterologous nucleic acid sequence in the host cell to modify the production of the carotenoids in the host cell, relative to an untransformed host cell.
REFERENCES:
patent: 5453565 (1995-09-01), Mawson
patent: 5744341 (1998-04-01), Cunningham, Jr. et al.
patent: 5811273 (1998-09-01), Misawa et al.
patent: 5910433 (1999-06-01), Kajwara et al.
Arent Fox Kintner Plotkin & Kahn
Saidha Tekchand
University of Maryland
LandOfFree
Carotenoid ketolase genes and gene products, production of... does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Carotenoid ketolase genes and gene products, production of..., we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Carotenoid ketolase genes and gene products, production of... will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-3060429