Is the Α-Helix a Molecular Diode? Model of Α-Helix Electron Channel in Photosynthetic Reaction Centers
Science Direct Working Paper No S1574-0331(04)70922-4
10 Pages Posted: 8 Jun 2017 Last revised: 27 Jan 2018
Date Written: December 2002
Abstract
The α-helix is a rod-like structure in which the tightly coiled polypeptide chain forms the cylindrical backbone, with all the peptide dipoles aligning at one direction parallel to the helical axis. For the first time, a new concept is proposed that the central cavity of the α-helix backbone can be used to transport electrons. The electric field generated by the α-helix dipole facilitates electron transfer from a donor (upon photo-excitation) to an acceptor through the interior of the helix via field effect. This facilitated electron channel, like a molecular diode, possesses characteristic directionality, providing high efficiency and specificity for long-range electron transfer in photosynthetic reaction centers. Recent experiments have also emerged to provide evidences supporting this new concept. The model of α-helix electron channel bears great implication on designing novel molecular electronics and solar energy devices.
Keywords: α-helix, electron transfer, channel, field effect, photosynthesis, molecular device
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