A step ahead: combining protein purification and correct folding selection.

The success of recombinant protein expression seems unpredictable and even good yields of soluble proteins do not guarantee the correct folding. The search for soluble constructs can be performed by exploiting libraries and speeded up by automation, but these approaches are money and time consuming and the tags used for affinity purification can mask the real stability of the target proteins. The ideal purification protocol would include the structure quality control. A recent paper commented in this article describes a phage-display method to screen for antibodies that are able to re-fold after heat-denaturation and can be selectively affinity-purified only if monodispersed. It turned out that the proteins with high recovery performance after heat-shock were also suitable for efficient recombinant expression.