Structural insights of the MLF1/14‐3‐3 interaction

Myeloid leukaemia factor 1 (MLF1) binds to 14‐3‐3 adapter proteins by a sequence surrounding Ser34 with the functional consequences of this interaction largely unknown. We present here the high‐resolution crystal structure of this binding motif [MLF1(29–42)pSer34] in complex with 14‐3‐3ε and analyse the interaction with isothermal titration calorimetry. Fragment‐based ligand discovery employing crystals of the binary 14‐3‐3ε/MLF1(29–42)pSer34 complex was used to identify a molecule that binds to the interface rim of the two proteins, potentially representing the starting point for the development of a small molecule that stabilizes the MLF1/14‐3‐3 protein–protein interaction. Such a compound might be used as a chemical biology tool to further analyse the 14‐3‐3/MLF1 interaction without the use of genetic methods. Database Structural data are available in the Protein Data Bank under the accession number(s) 3UAL [14‐3‐3ε/MLF1(29–42)pSer34 complex] and 3UBW [14‐3‐3ε/MLF1(29–42)pSer34/3‐pyrrolidinol complex] Structured digital • 14‐3‐3 epsilon and MLF1 bind by x‐ray crystallography (View interaction) • 14‐3‐3 epsilon and MLF1 bind by isothermal titration calorimetry (View Interaction: 1, 2) Myeloid leukemia factor 1 (MLF1) is a protein implicated in the development of acute myeloid leukaemia. We report the crystal structure of [MLF1(29‐42)pSer34] in complex with 14‐3‐3ε and propose a chemical biology approach employing small molecules that can modulate the MLF1/14‐3‐3 interaction. As a first step, we present a molecule identified by fragment‐based ligand discovery that is binding to the interface of 14‐3‐3 and MLF1.