ELECTRON MOVEMENT THROUGH PROTEINS AND DNA

Nature utilizes the phenomenon of single electron transfer very widely , especially in metallo-proteins. In systems when the metal donor (D) is well separated from the acceptor (A) by polypeptide chains, the tra nsferring electron is presumed to be bonded, in part, by these chains, which may influence the pathway taken. This situation can be probed b y radiolytic injection of electrons into proteins at low temperatures. One aim of this brief review is to consider how information derived f rom such radiolysis studies, and followed by ESR spectroscopy, may pos sibly impinge on studies of D-A systems. Electrons can also be injecte d into duplex DNA in this way, and the results are compared with those for proteins. They are also considered in the light of recent studies of D-A electron-transfer via a polynucleotide strand. It seems that s uch transfers are very efficient, and it is tentatively suggested that Nature may also use this conductivity in some as yet undiscovered sys tems. (C) 1997 Elsevier Science Inc.