Molecular engineering of insulin for recombinant expression in yeast

Half of the global insulin supply for pharmaceutical application is produced using recombinant secretory expression by the yeast Saccharomyces cerevisiae.Molecular adaptation of insulin is necessary for secretory expression in S. cerevisiae.The effectiveness of insulin precursor expression by S. cerevisiae is determined by two main factors: dimerisation of insulin precursors and the thermodynamic folding stability of the insulin precursor.Insulin precursors can be adapted for highly efficient expression in S. cerevisiae by introducing removable structural elements that modify self-association properties and/or folding stability.Optimising large-scale production of insulin precursors, through structural adaptations for enhanced expression efficiency, is important to decrease CO2 emissions and conserve water and energy. Since the first administration of insulin to a person with diabetes in 1922, scientific contributions from academia and industry have improved insulin therapy and access. The pharmaceutical need for insulin is now more than 40 tons annually, half of which is produced by recombinant secretory expression in Saccharomyces cerevisiae. We discuss how, in this yeast species, adaptation of insulin precursors by removable structural elements is pivotal for efficient secretory expression. The technologies reviewed have been implemented at industrial scale and are seminal for the supply of human insulin and insulin analogues to people with diabetes now and in the future. Engineering of a target protein with removable structural elements may provide a general approach to yield optimisation. Since the first administration of insulin to a person with diabetes in 1922, scientific contributions from academia and industry have improved insulin therapy and access. The pharmaceutical need for insulin is now more than 40 tons annually, half of which is produced by recombinant secretory expression in Saccharomyces cerevisiae. We discuss how, in this yeast species, adaptation of insulin precursors by removable structural elements is pivotal for efficient secretory expression. The technologies reviewed have been implemented at industrial scale and are seminal for the supply of human insulin and insulin analogues to people with diabetes now and in the future. Engineering of a target protein with removable structural elements may provide a general approach to yield optimisation.