Abhishek Cukkemane

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Many receptors and ion channels are activated by ligands. One key question concerns the binding mechanism. Does the ligand induce conformational changes in the protein via the induced-fit mechanism? Or does the protein preexist as an ensemble of conformers and the ligand selects the most complementary one, via the conformational selection mechanism? Here,(More)
Ion channels gated by cyclic nucleotides have crucial roles in neuronal excitability and signal transduction of sensory neurons. Here, we studied ligand binding of a cyclic nucleotide-activated K(+) channel from Mesorhizobium loti and its isolated cyclic nucleotide-binding domain. The channel and the binding domain alone bind cyclic AMP with similar(More)
Biomolecular applications of NMR spectroscopy are often merely associated with soluble molecules or magnetic resonance imaging. However, since the late 1970s, solid-state NMR (ssNMR) spectroscopy has demonstrated its ability to provide atomic-level insight into complex biomolecular systems ranging from lipid bilayers to complex biomaterials. In the last(More)
Ion channels gated by cyclic nucleotides serve multiple functions in sensory signaling in diverse cell types ranging from neurons to sperm. Newly discovered members from bacteria and marine invertebrates provide a wealth of structural and functional information on this channel family. A hallmark of classical tetrameric cyclic-nucleotide-gated channels is(More)
Disaccharides are well-known for their membrane protective ability. Interaction between sugars and multicomponent membranes, however, remains largely unexplored. Here, we combine molecular dynamics simulations and fluorescence microscopy to study the effect of mono- and disaccharides on membranes that phase separate into Lo and Ld domains. We find that(More)
Studying biomolecules at atomic resolution in their native environment is the ultimate aim of structural biology. We investigated the bacterial type IV secretion system core complex (T4SScc) by cellular dynamic nuclear polarization-based solid-state nuclear magnetic resonance spectroscopy to validate a structural model previously generated by combining in(More)
Potassium (i.e., K(+)) channels allow for the controlled and selective passage of potassium ions across the plasma membrane via a conserved pore domain. In voltage-gated K(+) channels, gating is the result of the coordinated action of two coupled gates: an activation gate at the intracellular entrance of the pore and an inactivation gate at the selectivity(More)
Solid-state Nuclear Magnetic Resonance can provide detailed insight into structural and dynamical aspects of complex biomolecules. With increasing molecular size, advanced approaches for spectral simplification and the detection of medium to long-range contacts become of critical relevance. We have analyzed the protonation pattern of a membrane-embedded ion(More)
The majority of known bacteriophages have long tails that serve for bacterial target recognition and viral DNA delivery into the host. These structures form a tube from the viral capsid to the bacterial cell. The tube is formed primarily by a helical array of tail tube protein (TTP) subunits. In phages with a contractile tail, the TTP tube is surrounded by(More)
There is increasing interest in the use of viruses as model systems for fundamental research and as templates for nanomaterials. In this work, the rodlike fd virus was subjected to chemical modifications targeting different solvent-exposed functional groups in order to tune its surface properties, especially reversing the surface charge from negative to(More)