Michelle Stowell

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High resolution x-ray diffraction data from crystals of the Rhodobacter sphaeroides photosynthetic reaction center (RC) have been collected at cryogenic temperature in the dark and under illumination, and the structures were refined at 2.2 and 2.6 angstrom resolution, respectively. In the charge-separated D+QAQB- state (where D is the primary electron donor(More)
The cytochrome bo3 ubiquinol oxidase complex from Escherichia coli contains two binding sites for ubiquinone(ol) (UQ(H2)). One of these binding sites, the ubiquinol oxidation site, is clearly in dynamic equilibrium with the UQ(H2) pool in the membrane. The second site has a high affinity for ubiquinone (UQ), stabilizes a semiquinone species, and is located(More)
The structure of the nitrogenase MoFe-protein from Azotobacter vinelandii has been refined to 2.0 A resolution in two oxidation states. EPR studies on the crystals indicate that the structures correspond to the spectroscopically assigned oxidized (P(OX)/M(OX)) and the native or dithionite-reduced (P(N)/M(N)) forms of the enzyme. Both MoFe-protein structures(More)
SETTING Treatment of multidrug-resistant tuberculosis (MDR-TB) is often based on drug susceptibility testing (DST) results; for this reason, rapid, simple DST methods are sought which could be applied in resource-poor countries. One such method is a nitrate reductase colorimetric assay known as the Griess method. In Peru, where the incidence rate of TB is(More)
There have been numerous instances in the recent literature where the properties of ubiquinol and cytochrome c terminal oxidases are compared. Here we specifically examine the cytochrome bo3-type ubiquinol oxidase from Escherichia coli and the cytochrome aa3-type cytochrome c oxidases. A second redox-active copper site (CuA) is present only in the(More)
Electron paramagnetic resonance (EPR) studies of succinate:ubiquinone oxidoreductase (SQR) from Paracoccus denitrificans have been undertaken in the purified and membrane-bound states. Spectroscopic "signatures" accounting for the three iron-sulfur clusters (2Fe-2S, 3Fe-4S, and 4Fe-4S), cytochrome b, flavin, and protein-bound ubisemiquinone radicals have(More)
The plethora of proposed chemical models attempting to explain the proton pumping reactions catalyzed by the CcO complex, especially the number of recent models, makes it clear that the problem is far from solved. Although we have not discussed all of the models proposed to date, we have described some of the more detailed models in order to illustrate the(More)
Considering the lack of effectiveness of current therapies to treat HIV disease, the authors present observations that provide a strong cogent argument for critically designed and meticulously performed clinical trials employing whole body hyperthermia with or without other therapeutic modalities. Only as a result of such clinical trials will it be possible(More)