Higher Yields of Posttranslationally Modified Proteins

QIAGEN developed the first commercially available in vitro kit based on insect cell lysates, which enabled efficient expression of a broad range of eukaryotic proteins with posttranslational modifications. The new EasyXpress Insect Kit II uses an optimized lysate production procedure to provide even higher yields.

Many eukaryotic proteins require posttranslational modifications (PTMs) to be able to fold or function correctly. The EasyXpress Insect Kit II uses highly productive Spodoptera frugiperda lysates, which contain everything required for protein expression and PTMs (e.g., enzymes, protein assemblies, membrane fractions, and ribosomes). In trials, the new kit enabled glycosylation, phosphorylation, or signal-peptide cleavage of numerous proteins, from 14–115 kDa. In contrast to rabbit reticulocyte lysate (RRL)-based systems there is no need to add extra membrane preparations when synthesizing proteins, and the lot-to-lot reproducibility of the lysates is much higher.

Optimized cell lysates in the EasyXpress Insect Kit II provide increased protein yields compared to the old kit and rabbit-reticulocyte–lysate—based systems. Now, each 50 µl reaction provides up to 2 µg protein. This is sufficient for initial screening in numerous applications, such as activity and small molecule inhibition assays, protein interaction assays, and solubility studies.