Open AccessHydrogen Tunneling in a Prokaryotic Lipoxygenase
Author(s) -
Cody A. Marcus Carr,
Judith P. Klinman
Publication year - 2014
Publication title -
biochemistry
Language(s) - Uncategorized
Resource type - Journals
SCImago Journal Rank - 1.43
H-Index - 253
eISSN - 1520-4995
pISSN - 0006-2960
DOI - 10.1021/bi500070q
Subject(s) - kinetic isotope effect , context (archaeology) , deuterium , chemistry , quantum tunnelling , hydrogen , chemical physics , biochemistry , physics , biology , condensed matter physics , atomic physics , paleontology , organic chemistry
A bacterial lipoxygenase (LOX) shows a deuterium kinetic isotope effect (KIE) that is similar in magnitude and temperature dependence to the very large KIE of eukaryotic LOXs. This occurs despite the evolutionary distance, an ~25% smaller catalytic domain, and an increase in Ea of ~11 kcal/mol. Site-specific mutagenesis leads to a protein variant with an Ea similar to that of the prototypic plant LOX, providing possible insight into the origin of evolutionary differences. These findings, which extend the phenomenon of hydrogen tunneling to a prokaryotic LOX, are discussed in the context of a role for protein size and/or flexibility in enzymatic hydrogen tunneling.