3FCJ: Nitroalkane oxidase: mutant402N crystallized with nitroethane

The proton transfer reaction between the substrate nitroethane and Asp-402 catalyzed by nitroalkane oxidase and the uncatalyzed process in water have been investigated using a path-integral free-energy perturbation method. Although the dominating effect in rate acceleration by the enzyme is the lowering of the quasiclassical free energy barrier, nuclear quantum effects also contribute to catalysis in nitroalkane oxidase. In particular, the overall nuclear quantum effects have greater contributions to lowering the classical barrier in the enzyme, and there is a larger difference in quantum effects between proton and deuteron transfer for the enzymatic reaction than that in water. Both experiment and computation show that primary KIEs are enhanced in the enzyme, and the computed Swain-Schaad exponent for the enzymatic reaction is exacerbated relative to that in the absence of the enzyme. In addition, the computed tunneling transmission coefficient is approximately three times greater for the enzyme reaction than the uncatalyzed reaction, and the origin of the difference may be attributed to a narrowing effect in the effective potentials for tunneling in the enzyme than that in aqueous solution.
PDB ID: 3FCJDownload
MMDB ID: 77802
PDB Deposition Date: 2008/11/21
Updated in MMDB: 2009/12
Experimental Method:
x-ray diffraction
Resolution: 2.4  Å
Source Organism:
Similar Structures:
Biological Unit for 3FCJ: tetrameric; determined by author and by software (PISA)
Molecular Components in 3FCJ
Label Count Molecule
Proteins (4 molecules)
Nitroalkane Oxidase
Molecule annotation
Chemicals (14 molecules)
* Click molecule labels to explore molecular sequence information.

Citing MMDB