C-terminal and internal sequences of a low molecular weight (LMW-s) type of glutenin subunit

Amino acid sequences have been determined for a 25-residue C-terminal peptide and for two 9-residue peptides, all derived from cyanogen bromide fragmentation of a low molecular weight glutenin subunit (LMW-GS) with the N-terminal sequence : serine-histidine-isoleucine-proline-glycine-(LMW-s type). Previously, only N-terminal amino acid sequences have been available for LMW-s types, which appear to be the predominant LMW-GS type in hexaploid and tetraploid wheats. N-terminal sequences and complete sequences based on DNA sequences have been available, however, for subunits of the LMW-m type. These have the N-terminal sequence : methionine-glutamic acid-threonine-serine-cysteine. All three peptides prepared from the LMW-s type subunit showed strong sequence similarities to LMW-m type subunits from hexaploid and tetraploid bread wheats. The 25-residue C-terminal fragment was 80% identical to DNA-derived sequences of specific LMW-m types. Two of the peptides contained cysteine and showed homology around these cysteines with LMW-m type sequences. The results support the basic similarity between LMW-s and LMW-m glutenin subunits.