Computational Insights into Five- versus Six-Coordinate Iron Center in Ferrous Soybean Lipoxygenase.

ABSTRACT: Soybean lipoxygenase (SLO) serves as a prototype for fundamental understanding of hydrogen tunneling in enzymes. Its reactivity depends on the active site structure around a mononuclear, nonheme iron center. The available crystal structures indicate five-coordinate iron, while magnetic circular dichroism experiments suggest significant populations of both five-coordinate (5C) and six-coordinate (6C) iron in ferrous SLO. Quantum mechanical calculations of gas phase models produce only 6C geometries. Herein mixed quantum mechanical/molecular mechanical (QM/MM) calculations are employed to identify and characterize the 5C and 6C geometries. These calculations highlight the importance of the protein environment, particularly two Gln residues in a hydrogen-bonding network with Asn694, the ligan

SUBMITTER: Yu T 

PROVIDER: S-EPMC5117133 | biostudies-literature | 2016 Sep

REPOSITORIES: biostudies-literature