Co-operative Electron Transfer: Superconduction in Biomolecular Structures?

Abstract

Long-range biological electron transfer with negligible energy dissipation has repeatedly been suggested without theoretical evidence. In order to examine whether superconduction may occur in sections of biological electron transfer chains non-linear electron transfer with autocatalytic feedback loops was investigated. Within this model, superconduction indeed arises as a consequence of entropy export due to the reduction of the degrees of freedom of electrons caused by non-linear feedback between electrons (or electron densities)—mediated by the molecular structure. To give this approach a more realistic aspect it is applied to superconducting copper oxide phases. Here the feedback is triggered by the effect of electrons on highest antibonding levels of Cu(II) oxide planes, on the bond distance and thus the a cell dimension. A dynamic phenomenological model is calculated which demonstrates the reduction of the degrees of freedom of holes (electrons) through slaving and superconduction as a consequence of co-operation. Coherent behavior of electrons is the consequence. Realistic resistivity-temperature curves were obtained. This implies, within this non-linear irreversible model, a superconduction mechanism in copper phases, which shows some basic analogy with BCS-like theories but explains why electrons remain correlated at higher temperature. It is concluded that co-operative electron transfer leading to superconduction in molecular structures at ambient temperature is in principle possible. The significance of this conclusion for electron transfer chains is discussed. The last four-electron-transfer step of photosynthetic oxygen evolution is considered to be a probable example. Co-operative electron transfer and superconduction guarantees oxygen evolution without formation of rate-determining intermediates.