Atomic description of an enzyme reaction dominated by proton tunneling

Laura Masgrau, Anna Roujeinikova, Linus O Johannissen, Parvinder Hothi, Jaswir Basran, Kara E Ranaghan, Adrian J Mulholland, Michael J Sutcliffe, Nigel S Scrutton, David Leys

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Abstract

We present an atomic-level description of the reaction chemistry of an enzyme-catalyzed reaction dominated by proton tunneling. By solving structures of reaction intermediates at near-atomic resolution, we have identified the reaction pathway for tryptamine oxidation by aromatic amine dehydrogenase. Combining experiment and computer simulation, we show proton transfer occurs predominantly to oxygen O2 of Asp(128)beta in a reaction dominated by tunneling over approximately 0.6 angstroms. The role of long-range coupled motions in promoting tunneling is controversial. We show that, in this enzyme system, tunneling is promoted by a short-range motion modulating proton-acceptor distance and no long-range coupled motion is required.
Original languageEnglish
Pages (from-to)237 - 241
Number of pages5
JournalScience
Volume312
Issue number5771
DOIs
Publication statusPublished - 2006
Externally publishedYes

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