Interprotein Electron Transfer Reaction Regulated by an Artificial Interface We thank Prof. Dr. I. Morishima and his group for the arrangement of laser flash photolysis equipment. This work was supported by Nagase Science and Technology Foundation, and a Grant-in-Aid for Scientific Research from the Ministry of Education, Science and Culture, Japan. Y. H. was supported by Research Fellowships of the Japanese Society for the Promotion of Science for Young Scientists.