Underpinning Biological Energy Transduction via Naphthalene Diimide Molecular and de novo Protein Constructs

Abstract

Naphthalene diimide (NDI) is a powerful excited-stated photoxidant that has enabled light-triggered oxidative processes to be investigated. In this dissertation, the synthetic and spectroscopic tunability of NDI is leveraged to underpin several essential biological energy transduction mechanisms, including pure electron transfer (ET), concerted proton coupled electron transfer (PCET), sequential electron transfer followed by proton transfer (ET-PT), and ratcheted ET. The ultimate goal of this work is to build energy transduction function from scratch in bioinspired de novo proteins that orchestrate the movement of electrons (e-s), holes (h+s), and protons (H+s) to redox-active amino acids using bound cofactors. This work leverages both experiment and theory to achieve this goal. The molecular energy transduction work outlined in this dissertation is currently being used to design de novo proteins that independently control the light-triggered flow of e-s, h+s, and H+s to enable both concerted and sequential flow of these charges. The presented work underpins the energy-transduction function of natural proteins, such as Photosystem II, and establishes the groundwork to engineer soft materials that produce high potential photoproducts, possess novel electro-optic function, and transduce energy via designed ET and PT pathways.