Although molecular recognition is crucial for cellular signaling, mechanistic studies have relied primarily on ensemble measures that average over and thereby obscure underlying steps. Single-molecule observations that resolve these steps are lacking due to diffraction-limited resolution of single fluorophores at relevant concentrations. Here, we combined zero-mode waveguides with fluorescence ...

A series of original heteroleptic dirhodium(II) complexes (4 a–j) formula [Rh2(OAc)3(L)], where L is a redox-active ferrocenecarboxylate ligand, has been prepared. These have characterised by NMR, mass spectrometry and cyclic voltammetry. All show quasi-reversible redox behaviour for the ferrocenyl unit. The latter can be selectively oxidised [N(4-C6H4Br)3]+BF4−. Four selected 4 a, b, f i, eval...

Bis-thiosemicarbazones derived from the ?-diketone benzoylacetone (H3banR, R=Me, Et, Ph) are potentially tetradentate N2S2 ligands whose coordination chemistry with copper is reported. In absence of oxygen and in presence base they form anionic CuII complexes fully deprotonated [CuII(banR)]–. Upon exposure to atmospheric undergo a complex series reactions leading two types products; one ligand ...

Ligand-protein binding processes are essential in biological systems. A well-studied system is the binding of cyclic adenosine monophosphate to the cyclic nucleotide binding domain of the bacterial potassium channel MloK1. Strikingly, the measured on-rate for cyclic adenosine monophosphate binding is two orders of magnitude slower than a simple Smoluchowski diffusion model would suggest. To res...

Cyclic nucleotide-gated (CNG) channels are activated in response to the direct binding of cyclic nucleotides to an intracellular domain. This domain is thought to contain a beta roll and two alpha helices, designated the B and C helices. To probe the conformational changes occurring in the ligand-binding domain during channel activation, we used the substituted cysteine accessibility method (SC...

Cyclic nucleotide-sensitive ion channels are molecular pores that open in response to cAMP or cGMP, which are universal second messengers. Binding of a cyclic nucleotide to the carboxyterminal cyclic nucleotide binding domain (CNBD) of these channels is thought to cause a conformational change that promotes channel opening. The C-linker domain, which connects the channel pore to this CNBD, play...

The cyclic nucleotide-gated (CNG) channel of retinal rod photoreceptor cells is an allosteric protein whose activation is coupled to a conformational change in the ligand-binding site. The bovine rod CNG channel can be activated by a number of different agonists, including cGMP, cIMP, and cAMP. These agonists span three orders of magnitude in their equilibrium constants for the allosteric trans...

The interaction of a small library of cyclic RGD (Arg-Gly-Asp) peptidomimetics with αVβ₆ integrin has been investigated by means of competitive solid phase binding assays to the isolated receptor and docking calculations in the crystal structure of the αVβ₆ binding site. To this aim, a rigid receptor-flexible ligand docking protocol has been set up and then applied to predict the binding mode o...

The Differential Radial Capillary Action of Ligand Assay (DRaCALA) allows detection of protein interactions with low-molecular weight ligands based on separation of the protein-ligand complex by differential capillary action. Here, we present an application of DRaCALA to the study of nucleic acid-protein interactions using the Escherichia coli cyclic AMP receptor protein (CRP). CRP bound in DRa...