Characterization of a low-molecular-weight glutenin subunit gene from bread wheat and the corresponding protein that represents a major subunit of the glutenin polymer.
Both high- and low-molecular-weight glutenin subunits (LMW-GS) play the major role in determining the viscoelastic properties of wheat (Triticum aestivum L.) 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. Extensive amino acid sequences obtained directly for this 42K LMW-GS indicate correspondence between this protein and 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 This Cys has been replaced by one occurring in the repeated-sequence domain, leaving the total number of Cys residues in the molecule the same as in various other LMW-GS. 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.
Masci
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Dipartimento di Agrobiologia e Agrochimica, Universita' della Tuscia, Via S. Camillo de Lellis, 01100 Viterbo, Italy. masci@unitus.it
D'Ovidio
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Lafiandra
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Kasarda
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D000595:Amino Acid Sequence; D001704:Biopolymers / Q000737:chemistry; D003001:Cloning, Molecular; D003198:Computer Simulation; D005433:Flour / Q000032:analysis; D005983:Glutens / Q000031:analogs & derivatives* / Q000737:chemistry / Q000235:genetics; D008958:Models, Molecular; D008969:Molecular Sequence Data; D008970:Molecular Weight; D010446:Peptide Fragments / Q000737:chemistry / Q000235:genetics; D016133:Polymerase Chain Reaction; D011487:Protein Conformation; D014908:Triticum / Q000737:chemistry* / Q000235:genetics*
D001704:Biopolymers; D010446:Peptide Fragments; D005983:Glutens; C037302:glutenin