Atomic description of an enzyme reaction dominated by proton tunneling.
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.
Masgrau
Laura
L
Manchester Interdisciplinary Biocentre, University of Manchester, Jackson's Mill, Post Office Box 88, Manchester M60 1QD, UK.
Roujeinikova
Anna
A
Johannissen
Linus O
LO
Hothi
Parvinder
P
Basran
Jaswir
J
Ranaghan
Kara E
KE
Mulholland
Adrian J
AJ
Sutcliffe
Michael J
MJ
Scrutton
Nigel S
NS
Leys
David
D
D042481:Alcaligenes faecalis / Q000201:enzymology*; D001224:Aspartic Acid / Q000737:chemistry; D001665:Binding Sites; D002384:Catalysis; D055598:Chemical Phenomena; D002627:Chemistry, Physical; D003198:Computer Simulation; D018360:Crystallography, X-Ray; D007700:Kinetics; D008956:Models, Chemical; D009038:Motion; D010084:Oxidation-Reduction; D000587:Oxidoreductases Acting on CH-NH Group Donors / Q000737:chemistry* / Q000378:metabolism*; D010100:Oxygen / Q000737:chemistry; D011522:Protons; D013696:Temperature; D013816:Thermodynamics; D014363:Tryptamines / Q000378:metabolism*; D014867:Water / Q000737:chemistry
D011522:Protons; D014363:Tryptamines; D014867:Water; D001224:Aspartic Acid; C030820:tryptamine; D000587:Oxidoreductases Acting on CH-NH Group Donors; C037193:aromatic amine dehydrogenase; D010100:Oxygen