The photoelectronic nature of a dried photosystern I protein attached to a metal surface is studied using various spectroscopic techniques. The proteins are found to be optically active after the chemical adsorption. In addition, energy-resolved photoelectronic measurements indicate that the interaction of photosystem I with the metal surface leads to new molecule/substrate states, yielding energy states different from those of the individual components. Such interactions increase the spectra I-response range beyond the absorption spectrum of photosystem I and are expected to improve the energy-conversion efficiency of devices based on this system.