An asparagine residue affects LMW-GS maturation processing
The low molecular weight glutenin subunits (LMW-GS) are represented by many heterogeneous proteins.The most common, based on the first amino acid of the mature sequence, are known as LMW-m and LMW-s types.These differ as a consequence of three extra amino acids at the N-terminus of LMW-m types.The nucleotide sequences of their encoding genes are in fact nearly identical, so that it is not easy to ascertain the exact N-terminal amino acid sequence on the basis of the nucleotide sequence.It was hypothesized that the presence of an asparagine residue in position 23 of the coding sequence might account for the processing of the N-terminal end of the LMW-s sequence.The resulting cleavage by an asparagine protease would generate the observed N-terminus of the LMW-s type.Conversely, replacement of the asparagine residue by a threonine would generate the LMW-m type N-terminal sequence.We performed site directed mutagenesis of a LMW-s gene to replace asparagine at position 23 with threonine and the converse to a LMW-m type gene.Next we produced transgenic durum lines.These were transformed with the mutated versions of the LMW-m and LMW-s genes along with the wild type counterpart of the LMW-m type gene.Western blot analyses on 2D gels and proteomic comparisons between the transgenic and untransformed lines enabled identification of the transgenic proteins.MS/MS analyses and Edman N-terminal amino acid sequences confirmed that processing occurs according to our predictions.
E.Egidi M.Janni F.Sestili A.Ceriotti R.DOvidio D.Lafiandra D.D.Kasarda W.H.Vensel S.Masci
DAFNE, Tuscia University, Viterbo, Italy DAFNE, Tuscia University, Viterbo, Italy;IGV, CNR, Bari, Italy IBBA, CNR, Milan, Italy USDA, ARS,WRRC, Albany, CA, U.S.A
国际会议
The 11th International Gluten Workshop(第十一届国际谷蛋白学术研讨会)
北京
英文
31-33
2012-08-12（万方平台首次上网日期，不代表论文的发表时间）