Adsorption of light-sensor protein AnPixJ to the silica nanoporous materials

Abstract

AnPixJ is a novel cyanobacteriochrome of a cyanobacterium Anabaena(Nostoc)sp. PCC 7120. Upon the irradiation of red- light and green-light, it shows a reversible photoconversion between a green-absorbing (λ_max=543 nm) and red-absorbing (λ_max=648 nm) forms. His-tagged chromophore-binding GAF domain of AnPixJ protein (AnPixJ-GAF) with a molecular weight of about 20 kDa was purified by using Ni affinity column. We introduced this water-soluble protein into SiO2 mesoporous materials and tested its photoconversion. AnPixJ introduced into a silica mesoporous material showed photoconversion activity. We studied the effects of pore diameter on the extent of the adsorption and photoconversion activity.