Cell-Free Expression of the Lhcb1 Protein of Arabidopsis Thaliana

We applied a cell-free expression system for in-vitro synthesis the Lhcb1 protein of Arabidopsis thaliana using a commercial in-vitro expression kit. The advantages of the cell-free system are that lipids or detergents can be added directly to the reaction mixture and that amino-acid residues can readily be substituted by isotope-labeled ones for studies by NMR. We carried out Lhcb1 batch-mode synthesis reactions in the presence of pigments and/or lipid nanodiscs. Interestingly, the Lhcb1 protein yield was significantly increased in the presence of lipid nanodiscs even though the majority of the synthesized proteins were obtained as precipitates. By optimizing the cell-free reaction mix parameters, we might eventually be able to refold and pigment-reconstitute the antenna complexes during the synthesis reaction.