Michael H. B. 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 GTPase dynamin plays an essential part in endocytosis by catalysing the fission of nascent clathrin-coated vesicles from the plasma membrane. Using preformed phosphatidylinositol-4,5-bisphosphate-containing lipid nanotubes as a membrane template for dynamin self-assembly, we investigate the conformational changes that arise during GTP hydrolysis by(More)
The nicotinic acetylcholine (ACh) receptor is the neurotransmitter-gated ion channel responsible for the rapid propagation of electrical signals between cells at the nerve/muscle synapse. We report here the 4.6 A structure of this channel in the closed conformation, determined by electron microscopy of tubular crystals of Torpedo postsynaptic membranes(More)
Dynamin is a large GTPase with a relative molecular mass of 96,000 (Mr 96K) that is involved in clathrin-mediated endocytosis and other vesicular trafficking processes. Although its function is apparently essential for scission of newly formed vesicles from the plasma membrane, the nature of dynamin's role in the scission process is still unclear. It has(More)
Synaptophysin I (SypI) is an archetypal member of the MARVEL-domain family of integral membrane proteins and one of the first synaptic vesicle proteins to be identified and cloned. Most all MARVEL-domain proteins are involved in membrane apposition and vesicle-trafficking events, but their precise role in these processes is unclear. We have purified(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)
We have purified the mammalian synaptophysin/synaptobrevin (SYP/VAMP2) complex to homogeneity in the presence of cholesterol and determined the 3D EM structure by single particle reconstruction. The structure reveals that SYP and VAMP2 assemble into a hexameric ring wherein 6 SYP molecules bind 6 VAMP2 dimers. Using the EM map as a constraint, a three(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)
With the recent successes in determining membrane protein structures, we explore the tractability of determining representatives for the entire human membrane proteome. This proteome contains 2,925 unique integral α-helical transmembrane domain sequences that cluster into 1,201 families *Corresponding authors: Andrej Sali, sali@salilab.org; Raymond C.(More)