Electron transfer in proteins, which contributes to many biological processes including DNA repair, is  strongly temperature dependent. Ultraviolet light damages DNA by forming cyclobutane pyrimidine dimer (CPD) lesions. Biological repair includes binding of the photolyase cofactor, flavin adenine dinucleotide (FAD), to the CPD, photo-excited electron transfer from FAD to the DNA lesion, cleavage of the dimer bonds and return of the electron to FAD.  We use theory to investigate the protein electron transfer near the freezing and boiling points of water in extremophiles through modeling and simulation of separated and docked photolyase � DNA species, aimed at understanding how structure and structural fluctuations of the protein-DNA complex influence the propensity for photochemical repair. In particular, we examine how repair propensities vary with temperature by combining conformational sampling with quantum calculations of electron tunneling interactions to explore electron transfer kinetics.

Protein electron transfer in extremeophiles

248th National Meeting (2014)

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