Cover picture: Escherichia coli FepA is a Gram-negative bacterial outer membrane protein that actively transports iron. When fluorescein was attached to the side chains (colored spheres) of amino acids in its surface loops, spectroscopic analyses revealed their dynamic actions during iron binding and transport. The loops individually adsorbed to the metal complex at different rates, like the fingers of two hands closing on an object (see research article by Smallwood et al., 71–80).
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A nonequilibrium binary elements-based kinetic model for benzodiazepine regulation of GABAA receptors
A nonequilibrium kinetic model that explicitly treats the energetics of interactions between structural domains is used to describe positive modulation of the GABAA receptor by benzodiazepines.
Preference for cGMP binding to a cyclic nucleotide–binding domain can achieved by compensating for ligand dehydration or through retention of solvation waters in the bound state.
Conductance and block of hair-cell mechanotransducer channels in transmembrane channel–like protein mutants
Proteins other than TMC1 and TMC2 must contribute to the pore of the mechanotransducer channel of cochlear hair cells; an external vestibule subject to disruption in Tmc mutants may influence the channel’s properties.
The loops of the bacterial outer membrane iron transporter FepA move at different rates to adsorb and grasp the substrate ferric enterobactin before transporting it into the periplasm.
Methods and Approaches
A P2X4 receptor labeled with the pH-sensitive GFP superecliptic pHluorin represents a useful probe to investigate P2X4 receptor distribution, trafficking, and up-regulation.
Computational analysis of target sequences from calmodulin–peptide structures indicates that calmodulin often binds to sequences with multiple overlapping canonical calmodulin-binding motifs.
Calcium-calmodulin does not alter the anion permeability of the mouse TMEM16A calcium-activated chloride channel
Ca2+-calmodulin fails to affect TMEM16A anion permeability.