Effect of chemical substitution on the surface charge of the photosynthetic Reaction Center from Rhodobacter sphaeroides: an in-silico investigation.

The Reaction Centers (RCs) proteins are membrane proteins representing the key component so flight energy transduction in photosynthetic organisms. Upon photon absorption, these photoenzymes produce a long lasting intra protein hole electron couples whose charges are separated by 3 nanometers. The dipoles formed within the RCs can be effectively employed as transducing cores of several biological-organic hybrid devices whose design can accomplish photocurrents generation or act as phototransistor. To widen the application of the RCs to as many substrate as possible one valuable strategy is the bioconjugation of the protein with specific molecules ad-hoc selected to improve enzymatic performance and/or integration in proper scaffolding. In the present manuscript, we investigate the changes of the isoelectric point of the RC from the carotenoidless strain of the photosynthetic bacterium Rhodobacter sphaeroides R26 by inducing "in silico" mutations to predict on the role of the aminoacids involved in the bioconjugation.