Isolation And Characterization Of A Low Molecular Weight Glutenin Subunit Gene From Aegilops

The low molecular weight glutenin subunit(LMW-GS) is the main component of wheat gluten.The LMW-GS account for about 40%fo the total gluten fraction and for 60-70%of the glutenins. The LMW-GS is one of the main factors that determine the nutritional and technological properties.Because of their large number and considerable heterogeneity, they are difficult to be separated by Sodium Dodecy1 Sulfate-Polyacrylamide Gel Electrophoresis (SDS-PAGE).The studies about LMW-GS are rare compared with HMW-GS and focus on primitive wheat and durum wheat.This paper study the LMW-GS gene utilizing the Aegilops cultivars. 1.Both high-and low-molecular-weight glutenin subunits (LMW-GS) play the major role in determining the viscoelastic properties of wheat flour. To date there has been no clear correspondence between the amino acid sequences of LMW-GS derived from DNA sequencing and those of actual LMW-GS present in the endosperm. We have characterized a particular LMW-GS from hexaploid bread wheat, a major component of the glutenin polymer, which we call the 42K LMW-GS, and have isolated and sequenced the putative corresponding gene. This subunit did not show a cysteine (Cys) at position 5'in contrast to what has frequently been reported for nucleotide-based sequences of LMW-GS. This Cys has been replaced by one occurring in the repeated-sequence domain, leaving the total number of Cys residues in the molecule the same as in various other LMW-GS. 2.On the basis of the deduced amino acid sequence and literature-based assignment of disulfide linkages, a computer-generated molecular model of the 42K subunit was constructed. We designed two pairs of primes according...