TY - JOUR
T1 - Impact of Mutations on the Binding Pocket of Soybean Lipoxygenase
T2 - Implications for Proton-Coupled Electron Transfer
AU - Li, Pengfei
AU - Soudackov, Alexander V.
AU - Hammes-Schiffer, Sharon
N1 - Publisher Copyright:
© 2018 American Chemical Society.
PY - 2018/11/15
Y1 - 2018/11/15
N2 - Soybean lipoxygenase catalyzes a proton-coupled electron transfer (PCET) reaction and serves as a prototype for hydrogen tunneling in enzymes due to the unusually high kinetic isotope effect and significant modulation of the rate constant and kinetic isotope effect by mutation. Herein these experimental observations are interpreted in the context of changes to the substrate binding pocket in microsecond molecular dynamics simulations of wild-type and mutant soybean lipoxygenase. The binding pocket exhibits an hourglass shape with residues L546 and L754 bracketing the bottleneck, positioning the linoleic acid substrate for PCET. Mutation of I553 to less bulky residues slightly increases the width of the bottleneck and the volume of the binding pocket. Mutating L546 or L754 to a smaller residue also enlarges this width and volume, and mutating both has an even more dramatic effect. This analysis illustrates how mutation of the substrate binding pocket can be used as a strategy to tune the kinetics.
AB - Soybean lipoxygenase catalyzes a proton-coupled electron transfer (PCET) reaction and serves as a prototype for hydrogen tunneling in enzymes due to the unusually high kinetic isotope effect and significant modulation of the rate constant and kinetic isotope effect by mutation. Herein these experimental observations are interpreted in the context of changes to the substrate binding pocket in microsecond molecular dynamics simulations of wild-type and mutant soybean lipoxygenase. The binding pocket exhibits an hourglass shape with residues L546 and L754 bracketing the bottleneck, positioning the linoleic acid substrate for PCET. Mutation of I553 to less bulky residues slightly increases the width of the bottleneck and the volume of the binding pocket. Mutating L546 or L754 to a smaller residue also enlarges this width and volume, and mutating both has an even more dramatic effect. This analysis illustrates how mutation of the substrate binding pocket can be used as a strategy to tune the kinetics.
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U2 - 10.1021/acs.jpclett.8b02945
DO - 10.1021/acs.jpclett.8b02945
M3 - Article
C2 - 30359035
AN - SCOPUS:85056645812
SN - 1948-7185
VL - 9
SP - 6444
EP - 6449
JO - Journal of Physical Chemistry Letters
JF - Journal of Physical Chemistry Letters
IS - 22
ER -