<br/>Electron transfer (ET) reactions are critical steps in enzymatic reactivity across a broad range of biological processes. ET has been also been revealed as a key step in the novel, oxidative mechanism of the newly discovered class of cellulose-degrading enzymes, lytic polysaccharide monooxygenases (LPMOs). Beyond the fundamental value of improving our understanding of this biochemical process, elucidation of LPMO's novel reactivity would also have far-reaching implications for biofuel production pretreatment processes. However, the complexity and sensitivity of ET through proteins poses a challenge for the development of reliable electronic structure models capable of predicting electron tunneling probabilities in protein, highlighting the need for improvement of theoretical tools in this field. The present work further develops and characterizes several recent theoretical advancements using molecular mechanics and quantum mechanics methodologies for the prediction of biological ET processes ranging from fast hopping processes, to single-step non-adiabatic tunneling mechanisms. Model peptides are designed and utilized for the characterization of these approaches, and to furthermore evaluate a spectrum of electronic properties of amino acid side chains. Additionally, through the study of these model systems, we depict the influence of individual amino acids and peptide sequences on available electron tunneling pathways. Through the application of these QM and MM methods, and the detailed knowledge gained from model systems, we report theoretical predictions of the novel ET reaction mechanisms in biomass-degrading enzymes.

Theoretical models of electron transfer processes in LPMOs and model peptide systems

249th National Meeting (2015)

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