The peptide substrate reacts at CuM in peptidylglycine a-hydroxylating monooxygenase (PHM) and an electron tunnels from CuH to CuM. PHM is unusual in that the shortest path for electron tunneling (~10A) is via a water filled cavity1. Oxygen consumption and product production remain fully coupled when His172, a ligand of CuH, is mutated to Ala even though the Cu reduction potential is undoubtedly affected2 . We estimate ET rate for the H172A PHM mutant given the rate of hydrogen atom extraction from the substrate3. Shifts in ?G and ? relative to PHM are established assuming pure electron tunneling. ET rate is further assessed using square barrier and tunneling pathway4 models.(1) R.L. Osborne and J.P. Klinman, Wiley Series of Reactive Intermediates in Chemistry and Biology 2011 8: 1-22. (2) N.M. Marshall et.al., Nature 2009 462:113. (3) J.P. Evans et.al., Biochemistry 2006 45:15419. (4) D.N. Beratan et.al., Science 1991 252:1285.

Mutation at CuH in peptidylglycine α-hydroxylating monooxygenase (PHM) shifts [Delta]G and λ for electron tunneling from CuH to CuM

243rd National Meeting (2012)

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