Fig. 1. Workflow of Bcr-Abl SH2 synthesis as d-target for mirror-image monobody screening.

The d-Bcr-Abl SH2 domain was prepared by native chemical ligation (NCL) and subsequent desulfurization from two fragments produced by solid-phase peptide synthesis (SPPS), as previously described³⁴. After refolding and structure validation, the d-target was subjected to monobody selection through phage and yeast display yielding l-monobody binders. Following binder characterization, most promising monobodies were synthesized in d-configuration resulting in d-monobodies targeting the natural l-Bcr-Abl SH2 domain.