CONTROL OF THE ORIENTATION OF PHOTOSYNTHETIC REACTION-CENTER PROTEINSUSING AN APPLIED BIAS-VOLTAGE LANGMUIR-BLODGETT TECHNIQUE

We investigated the orientation control of photosynthetic reaction cen ter proteins (RCs) by preparing RC Langmuir-Blodgett films in which a DC bias voltage ranging from -0.5V to +0.5 V was applied (using a pote ntiostat) during film deposition, The bias voltage was applied between a conductive indium-tin-oxide coated glass substrate and a subphase t hrough a helical platinum counter electrode. The orientation was evalu ated using displacement-curl ent measurement and photoelectron spectro scopy. Our results confirm that molecular orientation of RCs in the fi lms was controlled by the polarity of the applied voltage.