Protein Engineering and Modeling


Cristallisation helpers

Specific alphaReps binding to proteins that do not crystallize when isolated have been selected. The presence of specific alphaRep binders considerably improved the crystallization and was essential to solve the structure of these protein targets.

Structure of complexes between alpharep and cognates target proteins .
Each one of these protein cannot be crystallized when isolated, but did gave good crystals once bound to specific alpharep binders.

Expression in living cells

Due to the presence of disulfide bonds, most antibodies cannot be expressed in a functional form within living cells. AlphaReps are efficiently expressed in living cells, do not aggregate, and can bind their cognate targets . This opens new opportunities for protein interference experiments.

Figure alpharep are folded in living cells alphaRep are fused to m-cherry (red) . bGFPa, b, d are three different GFP-specific alphaRep. NS is a non relevant alphaRep. GFP (green) was expressed in dfifferent cell compartiments . When coexpressed with their target protein in mammalian cells, alphaRep are folded, soluble and co-localize with its target protein.


Some alphaReps designed with two domains are folded as a bivalve shell. The closed shell can open when the alphaRep binds its cognate targets. This conformational change can be detected by time resolved fluorescence (FRET) change between a luminescent lanthanide and a quantum dot. This provides the basis of a new type of biosensors.

Materials and nanoscience

Protein molecular recognition  are not restricted to biological partners. alphaReps binding preferentially to crystallographic plane (111) of Gold surface were selected. These proteins can then be used to change the growth of gold nanoparticles. It also solubilizes the protein coated nanoparticles and offers functional surface on synthetic nanoparticle to drive self-assembly between nano-particles

Artificial metalloenzymes

Artificial metalloenzymes can be engineered by coupling organometallic complexes into an alphaRep protein scaffold. Design and production of enantioselective biohybrids with allosteric properties provides a new class of artificial catalysts for chemical reactions in eco-compatible conditions.

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