Yeast platforms

For decades yeast expression technologies have served well academic and industrial protein production pipelines where the paramount requirements were high yields of therapeutic proteins, fast turnaround, stable and durable cell strains and cost effectiveness. As eukaryotic single-celled organisms, yeasts can perform many post-translational modifications, can handle disulfide-rich proteins, assist protein folding, and glycosylate and efficiently secrete proteins. They are also suitable hosts for selenomethionyl-incorporated and isotopically labeled protein expression. Last but not least, their well-known genetics and easily manipulable genomes make yeasts ideal systems for extensive customization of the expression strains.

And yet the two most frequent yeast systems for heterologous expression, S. cerevisiae and P. pastoris, are seriously handicapped by a lack of appropriate tools when it comes to preparing complex biologics that require the insertion of elaborate multigene production circuits. To bridge this gap and facilitate yeast-based high-throughput screening applications using protein complexes, the Vega group at the Center for Biological Research (CIB-CSIC) in Madrid, Spain, has designed and implemented the two ACEMBL suites MultiYeast and MultiPichia.

MultiYeast and MultiPichia consist of an acceptor plasmid that is tailored to each yeast platform plus several small donor vectors that can be used for fast and recyclable assembly of protein complexes. Additional vector elements enable high-throughput cloning and efficient selection of recombinant clones. The vector suites plus suitable standard, protease-deficient and humanized glycosylation yeast strains are available at the Vega lab for completely customized expression tests. Equipment and protocols for downstream processing and purification as well as for the thorough biophysical and biochemical characterization of the expressed products are also implemented.
The tight integration between MultiYeast/MultiPichia with the award-winning MultiBac system developed by the Berger lab allows the continuous improvement of the suites as a powerful and economic alternative for the high yield production of protein complex therapeutics.