Simultaneous Detection of Carbon Monoxide and Viscosity Changes in Cells

A new family of robust, non-toxic, water-compatible ruthenium(II) vinyl probes allows the rapid, selective and sensitive detection of endogenous carbon monoxide (CO) in live mammalian cells under normoxic and hypoxic conditions. Uniquely, these probes incorporate a viscosity-sensitive BODIPY fluorophore that allows the measurement of microscopic viscosity in live cells via fluorescence lifetime imaging microscopy (FLIM) while also monitoring CO levels. This is the first example of a probe that can simultaneously detect CO alongside small viscosity changes in organelles of live cells.     

Backward angle heavy ion elastic on 40Ca and 58Ni

The excitation functions of elastic scattering at 180° for ¹⁶O + ⁴⁰Ca and ¹²C + ⁴⁰Ca are observed to oscillate between $\text{σ}\text{σ}{}_{\mathrm{<mtext>R</mtext>}}\text{= 10}{}^{\mathrm{?3}}$ and 10^?4 over a wide range of energies; the ¹⁶O + ⁵⁸ Ni system shows a monotonic decrease to a value of $\text{σ}\text{σ}{}_{\mathrm{<mtext>R</mtext>}}\text{= 10}{}^{\mathrm{?5}}$ over the energy range studied.     

MD simulations of spontaneous membrane protein/detergent micelle formation

The in vitro study of membrane proteins for the purpose of physicochemical analysis or structure determination often relies upon successful reconstitution into detergent micelles. Moreover, a number of biological processes such as membrane protein folding and transport rely on lipid interactions which may resemble the micellar environment. Little is known about the structures of these micelles or the processes which lead to their formation. We therefore present two 50 ns all-atom molecular dynamics simulations of spontaneous dodecylphosphocholine micelle formation around representatives of the two major families of membrane proteins, a small beta-barrel protein, OmpA, and a model alpha-helical protein, glycophorin A. Despite differences in protein architecture, we highlight common mechanistic pathways in micelle formation, which are consistent with experimental studies. We characterize the exponential kinetics of detergent-protein adsorption and suggest a simple model which may explain the aggregation process. We also compare the results with 25 and 50 ns simulations of preformed micelles containing the same proteins. We confirm that the end structures of the self-assembled micelles are similar to those from their preformed counterparts, with each micelle presenting a bilayerlike environment to the enclosed protein.     

Dynamic combinatorial libraries of metalloporphyrins: templated amplification of disulfide-linked oligomers

Disulfide-linked cyclic porphyrin oligomers from dimer to tetramer can be selected and amplified virtually quantitatively from a dynamic combinatorial library using bis-thiol substituted zinc(II) porphyrin units with appropriate amine donor templates.