Aspects of intramolecular light energy and electron transfer will be discussed for three protein-cofactor complexes, whose three-dimensional structures have been elucidated by X-ray crystallography: components of lightharvesting cyanobacterial phycobilisomes; the purple bacterial reaction centre; and the blue multi-copper oxidases. A wealth of functional data is available for these systems which allows specific correlations between structure and function and general conclusions about light energy and electron transfer in biological materials to be made. | The EMBO Journal , 1989 NOBEL LECTURE A structural basis of light in biology * energy Robert Huber Max-Planck-Institut fiir Biochemie, D-8033 Martinsried, FRG *Dedicated to Christa. Aspects of intramolecular light energy and electron transfer will be discussed for three protein-cofactor complexes, whose three-dimensional structures have been elucidated by X-ray crystallography: components of lightharvesting cyanobacterial phycobilisomes; the purple bacterial reaction centre; and the blue multi-copper oxidases. A wealth of functional data is available for these systems which allows specific correlations between structure and function and general conclusions about light energy and electron transfer in biological materials to be made. Introduction All life on Earth depends ultimately on the sun, whose radiant is captured by plants and other organisms capable of growing by photosynthesis. They use sunlight to synthesize organic substances which serve as building materials or stores of energy. This was clearly formulated by , who stated that 'there exists between the sun and the earth a colossal difference in temperature.'. The equalization of temperature between these two bodies, a process which must occur because it is based on the law of probability will, because of the enormous distance and magnitude involved, last millions of years. The energy of the sun may, before reaching the temperature of the earth, assume improbable transition forms. It thus becomes possible to utilize the temperature drop between the sun and the earth to perform work as is the case with the temperature drop between steam and water '.To make the most use of this transition, green plants spread the enormous surface of their leaves and, in a still unknown way, force the energy of the sun to carry out chemical syntheses before it cools down to the temperature level of the Earth's surface. These chemical syntheses are to us in our laboratories .
