NEB offers chemically competent Kluyveromyces lactis GG779 cells suitable for transformation with a linearized pKLAC-series expression vector. We also provide variants of this strain tailored for specific protein expression needs. For example, chemically competent Kluyveromyces lactis YCT284 (∆cts1) cells are a preferred host for secreting heterologous proteins carrying a chitin-binding domain tag, and can be transformed with any linearized pKLAC-series expression vector.
Proteolysis of secreted heterologous proteins in K. lactis can be an issue in some applications and is most often caused by aspartyl proteases that are present in the secretory pathway. In many cases, a single aspartyl protease causes the majority of the detrimental protein degradation. The Protease Deficient Competent Cell Sampler contains a wild-type GG799 strain, as well as four protease deficient K. lactis strains, each having selectable marker-free deletion of a specific secretory pathway aspartyl protease gene. Each strain can be transformed with any linearized pKLAC-series expression vector, permitting a comparison of heterologous protein quality and yield in each background.