USOO5882851A United States Patent (19) 11 Patent Number: 5,882,851 K0ch et al. (45) Date of Patent: Mar 16, 1999 54 CYTOCHROME P-450 MONOOXYGENASES Halkier, et al., “The Biosynthesis of Cyanogenic Glucosides in Higher Plants”, The Journal of Biological Chemistry, 75 Inventors: Birgit Maria Koch, Vanløse; Ole 264(33): 19487–19494 (1989). Sibbesen, Roskilde; Barbara Ann Halkier, et al., “BioSynthesis of the Cyanogenic Glucoside Halkier, Copenhagen V; Birger Dhurrin in Seedlings of Sorghum bicolor (L.) Moench and Lindberg Moller, Brønshøj, all of Partial Purification of the Enzyme System Involved”, Plant Denmark Physiol, 90: 1552–1559 (1989). Halkier, et al., “Cyanogenic glucosides: the biosynthetic 73 Assignees: Novartis Finance Corporation, New pathway and the enzyme System involved”, Department of York, N.Y.; Royal Veterinary Plant Physioology, Royal Veterinary and Agricultural Uni Agricultural University, Copenhagen, versity, 40: 49-66 (1988). Denmark Halkier, et al., “The Biosynthesis of Cyanogenic Glucosides 21 Appl. No.: 656,177 in Higher Plants”, The Journal of Biological Chemistry, 265(34): 21114-21121 (1990). 22 PCT Filed: Nov. 28, 1994 Halkier, et al., “Involvement of Cytochrome P-450 in the Biosynthesis of Dhurrin in Sorghum bicolor (L.) Moench”, 86 PCT No.: PCT/EP94/03938 Plant Physiol, 96:10–17 (1991). S371 Date: Aug. 8, 1996 Halkier, et al., “2-Nitro-3-(p-hydroxyphenyl)propionate and aci-1-nitro-2-(p-hydroxyphenyl)ethane, two interme S 102(e) Date: Aug. 8, 1996 diates in the biosynthesis of the cyanogenic glucoside dhur rin in Sorghum bicolor (L.) Moench', Proc. Natl. Acad. Sci., 87 PCT Pub. No.: WO95/16041 88: 487–491 (1991). PCT Pub. Date:Jun. 15, 1995 Koch, et al., “The biosynthesis of cyanogenic glucosides in Seedlings of cassava (Manihot esculenta Crantez).’, 30 Foreign Application Priority Data Archives of Biochemistry and Biophysics, 292: 141-150 Dec. 8, 1993 EP European Pat. Off. .............. 93810860 (1992). Sibbesen et al., “Purification of the Hydroxylating Enzyme 51 Int. Cl. ............................... C12O 1/00; C12O 1/26; System Involved in the Biosynthesis of the Cyanogenic G01N 33/53; CO7H 19/00 Glucoside Dhurrin in Sorghum Bicolor (1.) Moench', Bio 52 U.S. Cl. .................................. 435/4; 435/7.1; 435/25; chemistry and Biophysics of Cytochrome P450, 232 (1991). 536/22.1 Primary Examiner Ardin H. Marschel 58 Field of Search ............................. 536/22.1; 435/7.1, Assistant Examiner-Jezia Riley 435/4, 25; 800/205 Attorney, Agent, or Firm J. Timothy Meigs; Gary M. Pace 56) References Cited 57 ABSTRACT FOREIGN PATENT DOCUMENTS New cytochrome P-450 dependent monooxygenases and O 281 245 A2 2/1988 European Pat. Off.. DNA molecules encoding these monooxygenases are O 522880 A3 7/1992 European Pat. Off.. provided, which are able to catalyze the biosynthetic path WO 91/10745 1/1991 WIPO. way from amino acids to their corresponding cyanohydrins, WO 93/04174 8/1992 WIPO. the preSursors of the cyanogenic glycosides, or to glucosi WO 93/21326 4/1993 WIPO. nolates. Moreover, the invention provides methods for obtaining DNA molecules according to the invention and OTHER PUBLICATIONS methods for obtaining transgenic plants resistant to insects, Gabriac, et al., “Purification and Immunocharacterization of acarids, or nematodes or plants with improved nutritive a Plant Cytochrome P450: The Cinnamic Acid 4-Hydroxy value. lase”, Archives of Biochemistry and Biophysics, 288(1): 302-309 (1991). 42 Claims, No Drawings 5,882,851 1 2 CYTOCHROME P-450 MONOOXYGENASES Biochemistry and Biophysics of cytochrome P-450. Struc ture and Function, Biotechnological and Ecological This application is a S371 of PCT/EP94/03938, filed on Aspects, Archakov, A. I. (ed.), 1991, Koch et al, 8th Int. Nov. 28, 1994, and published on Jun. 15, 1995, as WO Conf. on Cytochrome P450, Abstract PII.053; and Sibbesen 95/16041, which claims priority of European Patent Appli et al, 8th Int. Conf. on Cytochrome P450, Abstract PII.016). cation No. 93810860.2, filed on Dec. 8, 1993. It has been found that L-Tyrosine is converted to p-hydroxy The present invention relates to genetic engineering in mandelo nitrile, the precursor of dhurrin with plants using recombinant DNA technology in general and to N-hydroxytyrosine and supposedly N,N-dihydroxytyrosine, enzymes involved in the biosynthesis of cyanogenic glyco 2-nitroSO-3-(p-hydroxyphenyl)propionic acid, (E)- and (Z)- Sides and glucosinolates and genes encoding these enzymes 1O p-hydroxyphenylace taldehy d o Xime, and in particular. The proteins and genes according to the p-hydroxyphenylacetonitrile as key intermediates. Two invention can be used to improve the nutritive value or pest monooxygenases dependent on cytochrome P-450 have resistance of plants. been reported to be involved in this pathway. A similiar Cyanogenic glycosides constitute Secondary plant pathway also involving cytochrome P-450 dependent metabolites in more than 2000 plant species. In some 15 monooxygenases has been demonstrated for the Synthesis of instances they are the source of HCN which can render a linamarin and lotaustrain from Valine and isoleucine respec plant toxic if it is taken as food. For example the tubers of tively in cassava (Koch et al., Archives of Biochemistry and the cyanogenic crop cassava (Manihot esculenta) constitute Biophysics, 292: 141-150, 1992). an important Staple food in tropical areas. However, the It has now Surprisingly been found that the complex cyanogenic glycosides present in the tuberS may cause pathway from L-tyrosine to p-hydroxy-mandelonitrile Sum cyanide poisoning in humans due to insufficiently processed marized above can be reconstituted by two enzymes only, cassava products. Other plant Species whose enzymatic which turn out to be identical to the cytochrome P-450 production of HCN accounts for their potential toxicity if dependent monooxygenases. This result is very Surprising taken in exceSS as food or used as animal feed include white given the high degree of complexity of the pathway reflected clover (Trifolium repens), sorghum (Sorghum bicolor), linen 25 by its numerous intermediates. Thus the two cytochrome flax (Linum usitatissimum), triglochinin (Triglochin P-450 monooxygenases are multifunctional. A first enzyme, maritima), lima beans (Phaseolus lunatus), almonds designated P-450, converts the parent amino acid to the (Amygdalus) and Seeds of apricot (Prunus), cherries and Oxime. A second enzyme, designated P-450, converts the apple (Malus). The toxic properties could be reduced by oxime to the cyanohydrin. Multifunctional cytochrome blocking the biosynthesis of cyanogenic glycosides in these P-450 enzymes have not previously been found and plants. described in plants. The primary precursors of the naturally occuring cyano Glucosinolates are hydrophilic, non-volatile thioglyco genic glycosides are restricted to the five hydrophobic sides found within several orders of dicotyledoneous protein amino acids Valine, leucine, isoleucine, phenylala angiosperms (Cronquist, 'The Evolution and Classification nine and tyrosine and to a Single non-protein amino acid, 35 of Flowering Plants, New York Botanical Garden, Bronx, cyclopentenylglycine. These amino acids are converted in a 1988). Of greatest economic significance is their presence in Series of reactions to cyanohydrins which are ultimately all members of the Brassicaceae (order of Capparales), linked to a Sugar residue. Amygdalin for example constitutes whose many cultivars have for centuries provided mankind the O-B-gentiobioside and prunasin the O-3-glucoside of with a Source of condiments, relishes, Salad crops and (R)-mandelonitrile. Another example of cyanogenic glyco 40 vegetables as well as fodders and forage crops. More Sides having aromatic aglycones is the epimeric pair of the recently, rape (especially Brassica napuS and Brassica cyanogenic glycosides dhurrin and taxiphyllin which are to campestris) has emerged as a major oil seed of commerce. be found in the genus Sorghum and Taxus, respectively. About 100 different glucosinolates are known possessing the p-Hydroxymandelo-nitrile for example is converted into Same general Structure but differing in the nature of the Side dhurrin by a UDPG-glycosyltransferase. Similiar glycosyl 45 chain. Glucosinolates are formed from protein amino acids transferases are believed to be present in most plants. either directly or after a single or multiple chain extension Vicianin and lucumin are further examples for disaccharide (Underhill et al, Biochem. Soc. Symp. 38:303-326, 1973). derivatives similiar to amygdalin. Sambunigrin contains N-hydroxy amino acids and aldoximes which have been (S)-mandelonitrile as its aglycone and is therefore epimeric identified as intermediates in the biosynthesis of cyanogenic to prunasin. 50 glycosides also serve as efficient precursors for the biosyn Examples of cyanogenic glycosides having aliphatic thesis of glucosinolates (Kindl et al., Phytochemistry aglycones are linamarin and lot australin found in clover, 7:745-756, 1968; Matsuo et al., Phytochemistry 11:697–701, linen flax, cassava and beans. A detailed review on cyano 1972; Underhill, Eur. J. Biochem. 2:61-63, 1967). genic glycosides and their biosynthesis can be found in It has now Surprisingly been found that the cytochrome Conn, Naturwissenschaften 66:28-34, 1979, herein incor 55 P-450 involved in cyanogenic glycoside Synthesis is very porated by reference. Similiar to the corresponding biosynthetic enzyme in glu The biosynthetic pathway for the cyanogenic