Chemistry: molecular biology and microbiology – Plant cell or cell line – per se ; composition thereof;... – Plant cell or cell line – per se – contains exogenous or...
Reexamination Certificate
1996-08-30
2001-01-16
Smith, Lynette R. F. (Department: 1638)
Chemistry: molecular biology and microbiology
Plant cell or cell line, per se ; composition thereof;...
Plant cell or cell line, per se, contains exogenous or...
C435S410000, C435S069100, C435S419000, C800S278000, C800S284000, C800S290000, C800S320300, C426S456000
Reexamination Certificate
active
06174725
ABSTRACT:
INTRODUCTION
1. Field of the Invention
The invention relates to changing mechanical properties of wheat dough used to make products like breads and noodles by using modified glutenin proteins.
2. Background
Wheat cultivation began somewhere in the middle east and has been ongoing for perhaps as long as 10,000 years. Today, wheat rice and maize form the foundation of the human diet in every corner of the world. Of these, wheat is the most widely grown, and because of its high protein content, wheat is the single greatest source of protein in human diet.
Wheat is also unique because the mixture of flour and water produces a dough with unusual physical properties such as viscoelasticity. The rheological properties of dough can be attributed to many flour components, but the clearest association is with the storage proteins of the grain and flour. These proteins are historically divided into several families, of which the high molecular weight (HMW) glutenins, correlates best with dough viscoelasticity and bread-making quality. The deduced amino acid sequences of HMW glutenins reveal a dominant central repetitive domain composed of 45-90 repeats of two or three simple peptide motifs and non-repetitive terminal domains containing one or more cysteine residues.
It is believed that fundamental to dough functionality is the integrity of a highly cross-linked matrix formed by intermolecular disulfide linkages. For example, disruption of this network, such as by partial reduction, leads to loss of dough functional properties. Hence, the number and placement of cysteines sites in the HMW glutenin termini have been suggested to be determinants of viscoelastic properties of dough.
Comparisons of the HMW glutenins correlated with good and poor quality have also pointed to non-cysteine residues as being important viscoelastic determinants. For example, a glutenin known as subunit
10
is associated with good viscoelasticity and bread making quality, while subunit
12
is associated with poor viscoelasticity and bread making quality. These proteins are nearly identical with just twelve single amino acid substitutions, two hexamer repeat deletions (in subunit
10
), one 2-mer addition and one 2-mer deletion. Because of the two hexamer repeat deletions in subunit 10, it is slightly smaller in molecular weight than 12. Goldsbrough et al. (1989) Biochem J. 263, 837-842 have reported that the underlying conformational differences between these two similar proteins are due to a short region containing only six amino acid difference, none cysteines.
Relevent Literature
Anderson (1994) in Improvement of
Cereal Quality by Genetic Engineering
, Eds. Henry and Rolands, Plenum Press, N.Y., provides general background on wheat genetic engineering. Goldsbrough et al. (1989) Biochem J. 263, 837-842 report that conformational differences between two HMW subunits are due to a short region containing six amino acid differences. Bekes et al. (1994) J Cereal Science 19, 3-7 describe the use of a 2 g Mixograph for measuring the effects of a HMW glutenin subunit on dough mixing properties. Bekes et al. (1996), in
Improvement of Cereal Quality by Genetic Engineering
, Eds. Henry and Rolands, Plenum Press, NY, describe the contributions to mixing properties of HMW glutenins expressed in bacterial systems. Shani et al. (1992) Plant Physiol. 98, 433-441 report on the role of amino and carboxyl-terminal regions in the folding and oligomerization of HMW glutenin subunits. Blechl et al. (1996) Nature Biotechnology 14, 875-883, report the expression of a novel hybrid high molecular weight glutenin subunit gene in transgenic wheat.
SUMMARY OF THE INVENTION
The invention provides methods and compositions for producing dough, preferably wheat dough, with particular viscoelastic properties and the use of such dough in products such as breads and noodles. Viscoelastic variation is effected by using flour milled from seed containing non-natural HMW glutenin subunits. In particular, HMW glutenin subunits comprising a non-natural repetitive domain having repeats which are non-natural in number and/or synthetic in sequence are used to control viscoelastic properties of dough. It is demonstrated that while controlling for termini and repeat sequence, modifying repeat number may be used to change dough properties such as viscoelasticity. Hence, the repetitive domain is preferably of a non-natural glutenin subunit length, more preferably greater than a natural length.
The invention also provides recombinant genes encoding the subject HMW glutenin subunits, plants and seeds comprising such genes, and methods of making such plants by genetic engineering. The genes may encode natural repeat sequences recombined to encode proteins having preferably non-naturally long, repetitive domains. The genes may also contain non-synthetic or heterologous sequences which may be selected for preferential expression, secretion, etc. in a given host. The invention further provides doughs and other wheat products with modified viscoelastic properties and methods of making such product using the disclosed compositions.
REFERENCES:
patent: 5272072 (1993-12-01), Kaneko et al.
patent: 5650558 (1997-07-01), Blechl et al.
Anderson et al. (1989) Nuc. Acids Res. 17(1): 461-462, 1989.
Anderson et al. Nucleic Acid Research. 1989. vol. 17: 461-462.
Weeks et al. Plant Physiol. 1993. vol. 102: 1077-1084.
A. P. Goldsbrough, N. J. Bulleid, R. B. Freedman, and R. B. Flavell, “Conformational Differences Between Two Wheat (Triticum aestivum) ‘High-Molecular-Weight’ Glutenin Subunits are Due to a Short Region Containing Six Amino Acid Differences,”Biochem. J.263:837-842 (1989).
F. Bekes, P. W. Gras, R. B. Gupta, D. R. Hickman, and A. S. Tatham, “Effects of a High Mr Glutenin Subunity (1B×20) on the Dough Mixing Properties of Wheat Flour”Journal of Cereal Science19:3-7 (1994).
F. Bekes, O. Anderson, P. W. Gras, R. B. Gupta, A. Tam, C. W. Wrigley, and R. Appels, “The Contributions to Mixing Properties of 1D HMW Glutenin Subunits Expressed in a Bacterial System,” inImprovement of Cereal Quality by Genetic Engineering, Eds. R. Henry and J. A. Ronalds, Plenum Press, N.Y., pp. 97-103 (1994).
N. Shani, J. D. Steffen-Campbell, O. D. Anderson, F. C. Greene, and G. Galili, “Role of the Amino- and Carboxy-Terminal Regions in the Folding and Oligomerization of Wheat High Molecular Weight Glutenin Subunits,”Plant Physiol.98:433-441 (1992).
G. J. Lawrence, F. Macritchie, and C. W. Wrigley, “Dough and Baking Quality of Wheat Lines Deficient in Glutenin Subunits Controlled by the Glu-A1, Glu-B1 and Glu-D1 Loci,”Journal of Cereal Science7:109-112 (1988).
A. Blechl and O. Anderson, “Expression of a Novel High-Molecular-Weight Glutenin Subunit Gene in Transgenic Wheat,”Nature Biotechnology14:875-883 (1996).
Connor Margaret A.
Fado John D.
Silverstein M. Howard
Smith Lynette R. F.
The United States of America as represented by the Secretary of
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