Probing electron transfer of the redox species in wild-type RC protein andits pigment-replaced mutants re-constituted in self-assembly monolayers

The multi-layered protein film, containing photosynthetic reaction center ( RC) protein isolated from Rhodobacter sphaeriodes or its pigment-replaced m utants, was prepared with 4-Aminothiophenol (LF-ATP) self-assembled monolay er (SAM) modified gold electrode. The RC protein was embedded in an ordered -orientated charged poly-styrenesulfonate (PSS) and poly(dimerthyldiallylam monium) chloride (PDDA) film successively. The reversible or quasi-reversib le electron transfer (ET) for the re-constituted RC and its mutants was pro bed by cyclic voltammetry (CV) and square wave voltammetry (SWV), reflectin g the electrochemical-driven electron recombination for RC protein or its m utants. The SWV data for RC and its mutants in the films were nonlinearly f itted to get the electrochemical parameters.