Institut de Biologie StructuraleGrenoble / France

Crystallophore, an all-in-one tool for protein crystallography

Macromolecular crystallography suffers from two major issues: getting well-diffracting crystals and solving the phase problem inherent to large macromolecules. Here, a collaboration involving scientists from the IBS and from the ENS-Lyon describe the firstborn of a lanthanide complex family named “Crystallophore” (Xo4). The terbium complex, Tb-Xo4, facilitates protein crystallization, improves the quality of the crystals obtained and allows structure determination thanks to its exceptional phasing power. The collaboration demonstrate the potential of this additive for crystallisation and structure determination on eight proteins, two of whose structures were unknown. Xo4 contributes to tackle both bottlenecks of crystallopgraphy.
Xo4 technology has received financial support from ANR and SATT Pulsalys and is protected by patent n°WO2017103545. An exclusive license has been granted to POLYVALAN (, ENS-Lyon and IBS spin-off of , for the synthesis and commercialization of these molecules.

Crystallophore: a versatile lanthanide complex for protein crystallography combining nucleating effects, phasing properties, and luminescence.
Engilberge S, Riobe F, Di Pietro S, Lassalle L, Coquelle N, Arnaud CA, Pitrat D, Mulatier JC, Madern D, Breyton C, Maury O, Girard E. Chemical Science. DOI: 10.1039/c7sc00758b