| Autor: |
Fuller JT 3rd; Department of Chemistry and Biochemistry, University of California, Los Angeles, CA 90095., Barnes S; Department of Ophthalmology, David Geffen School of Medicine, University of California, Los Angeles, CA 90095.; Doheny Eye Institute, Pasadena, CA 91103.; Department of Neurobiology, David Geffen School of Medicine, University of California, Los Angeles, CA 90095., Sadun LA; Department of Mathematics, University of Texas at Austin, Austin, TX 78712., Ajmera P; Department of Chemistry and Biochemistry, University of California, Los Angeles, CA 90095., Alexandrova AN; Department of Chemistry and Biochemistry, University of California, Los Angeles, CA 90095., Sadun AA; Department of Ophthalmology, David Geffen School of Medicine, University of California, Los Angeles, CA 90095.; Doheny Eye Institute, Pasadena, CA 91103. |
| Abstrakt: |
How does a single amino acid mutation occurring in the blinding disease, Leber's hereditary optic neuropathy (LHON), impair electron shuttling in mitochondria? We investigated changes induced by the m.3460 G>A mutation in mitochondrial protein ND1 using the tools of Molecular Dynamics and Free Energy Perturbation simulations, with the goal of determining the mechanism by which this mutation affects mitochondrial function. A recent analysis suggested that the mutation's replacement of alanine A52 with a threonine perturbs the stability of a region where binding of the electron shuttling protein, Coenzyme Q10, occurs. We found two functionally opposing changes involving the role of Coenzyme Q10. The first showed that quantum electron transfer from the terminal Fe/S complex, N2, to the Coenzyme Q10 headgroup, docked in its binding pocket, is enhanced. However, this positive adjustment is overshadowed by our finding that the mobility of Coenzyme Q10 in its oxidized and reduced states, entering and exiting its binding pocket, is disrupted by the mutation in a manner that leads to conditions promoting the generation of reactive oxygen species. An increase in reactive oxygen species caused by the LHON mutation has been proposed to be responsible for this optic neuropathy. |
