In this part of our project we were planning to construct the system that would express streptavidin on yeast surface, and biotinylated aptamers would be used to make sandwich biosensor for CEA detection. The plasmid that was planned to be modified was pYES2: we were planning to insert Aga2 gene followed by (G4S)3 linker and then streptavidin gene, which was present in 2013 distribution kit (biobrick part BBa_J36847). The yeast, where pYES2 plasmid containing the expression system was planned to be inserted, was Saccharomyces cerevisiae. However, this part of the project was terminated because of the fact that we were not able to obtain mating type of yeast which was necessary for Aga2 gene, in association with Aga1 gene present in yeast itself, to express. Another obstacle was that we were not able to get the pure streptavidin sequence, thus gene construction was not performed.
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