Chemistry: molecular biology and microbiology – Enzyme – proenzyme; compositions thereof; process for... – Transferase other than ribonuclease
Reexamination Certificate
2000-01-04
2001-03-27
Achutamurthy, Ponnathapu (Department: 1652)
Chemistry: molecular biology and microbiology
Enzyme , proenzyme; compositions thereof; process for...
Transferase other than ribonuclease
C435S183000, C530S350000, C530S371000, C536S023200
Reexamination Certificate
active
06207433
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to isolated polypeptides having 5-aminolevulinic acid synthase activity and isolated nucleic acid sequences encoding the polypeptides. The invention also relates to nucleic acid constructs, vectors, and host cells comprising the nucleic acid sequences as well as methods for producing and using the polypeptides.
2. Description of the Related Art
Heme, a chelate complex of protoporphyrin IX and iron, serves as a prosthetic group of hemoproteins. Protoporphyrin IX consists of a porphyrin ring, substituted with four methyl groups, two vinyl groups, and two propionic acid groups, which acquires an iron atom to form heme. The biosynthesis of heme from glycine and succinyl-CoA involves eight enzymatic steps. The first enzyme in the biosynthetic pathway is 5-aminolevulinic acid synthase.
The conversion of an apoprotein into a hemoprotein depends on the availability of heme provided by the heme biosynthetic pathway. The apoprotein form of the hemoprotein combines with heme to produce the active hemoprotein. The active hemoprotein acquires a conformation which makes the hemoprotein more stable than the apoprotein to proteolytic attack. If the amount of heme produced by a microorganism is less relative to the amount of the apoprotein produced, the apoprotein will accumulate and undergo proteolytic degradation lowering the yield of the active hemoprotein.
In order to overcome this problem, Jensen showed that the addition of heme or a heme-containing material to a fermentation medium led to a significant increase in the yield of a peroxidase produced by
Aspergillus oryzae
(WO 93/19195). While heme supplementation of a fermentation medium results in a significant improvement in the yield of a hemoprotein, it is non-kosher, costly, and difficult to implement on a large scale.
The overexpression of a gene in the heme biosynthetic pathway of a cell provides an alternative approach for overcoming this problem.
The cloning and sequencing of a 5-aminolevulinic acid synthase gene from
Aspergillus nidulans
(Bradshaw et al., 1993,
Current Genetics
2233:501-507) have been disclosed.
It is an object of the present invention to provide new polypeptides having 5-aminolevulinic acid synthase activity and genes encoding same.
SUMMARY OF THE INVENTION
The present invention relates to isolated polypeptides having 5-aminolevulinic acid synthase activity selected from the group consisting of:
(a) a polypeptide having an amino acid sequence which has at least 80% identity with the amino acid sequence of SEQ ID NO:2;
(b) a polypeptide encoded by a nucleic acid sequence which hybridizes under high stringency conditions with (i) the nucleic acid sequence of SEQ ID NO:1 or (ii) its complementary strand; or a subsequence thereof of at least 100 nucleotides;
(c) an allelic variant of (a) or (b); and
(d) a fragment of (a), (b) or (c), wherein the fragment has 5-aminolevulinic acid synthase activity.
The present invention also relates to isolated nucleic acid sequences encoding the polypeptides and to nucleic acid constructs, vectors, and host cells comprising the nucleic acid sequences as well as methods for producing and using the polypeptides.
REFERENCES:
patent: 4902620 (1990-02-01), Bard et al.
patent: 5871991 (1999-02-01), Elrod et al.
patent: 0 505 311 (1992-09-01), None
patent: WO 93/19195 (1993-09-01), None
patent: WO 97/47746 (1997-12-01), None
Bradshaw et al., Curr Genet. vol. 23, pp. 501-507 (1993).
Achutamurthy Ponnathapu
Hutson Richard
Lambiris Esq. Elias
Novo Nordisk Biotech Inc.
Starnes Robert L.
LandOfFree
Polypeptides having aminolevulinic acid activity and nucleic... does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Polypeptides having aminolevulinic acid activity and nucleic..., we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Polypeptides having aminolevulinic acid activity and nucleic... will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-2504045