Yeast strains genetically engineered to produce wheat gluten proteins

摘要

A strain of yeast Saccharomyces cerevisiae has been developed which, when grown under defined culture conditions, will produce protein indistinguishable from wheat gluten protein. This new yeast strain was developed by introducing a specially constructed autonomously replicating extrachromosomal genetic element, gluten plasmid pAY31, into the parent yeast strain. This plasmid is a circular DNA molecule, constructed by enzymic fusion of the following elements: (1) the E. coli plasmid pUC8 wherein the EcoRI site has been removed; (2) the autonomously replicating yeast sequence ARS1; (3) the yeast URA3 gene; (4) a modified yeast iso-1- cytochromic gene retaining the promoter region and transcription termination sequence, and wherein the protein coding sequences have been deleted and replaced with a synthetic EcoRI restriction site, the site at which the wheat gluten protein gene is cloned; and (5) a fragment of a wheat gluten protein gene which includes the amino acid coding region, translation initiation and termination sequence, and short flanking nucleotide sequences, but excludes transcription initiation and termination sequences. Wheat gluten protein synthesized by the new yeast strain can be used to supplement wheat and non-wheat flours for baked products and for use in diagnosis and treatment of illness in humans caused by wheat gluten proteins.