We studied the interactions of strychnine, brucine, and three of the N-substituted analogues of brucine with [3H]N-methylscopolamine (NMS) and unlabeled acetylcholine at m1-m5 muscarinic receptors using equilibrium and nonequilibrium radioligand binding studies. The results were consistent with a ternary allosteric model in which both the primary and allosteric ligands bind simultaneously to th...

In a multimeric receptor protein, the binding of a ligand can modulate the binding of a succeeding ligand. This phenomenon, called cooperativity, is caused by the interaction of the receptor subunits. By using a complex Markovian model and a set of parameters determined previously, we analyzed how the successive binding of four ligands leads to a complex cooperative interaction of the subunits ...

Regulatory networks in cells may comprise a variety of types of molecular interactions. The most basic are pairwise interactions, in which one species controls the behaviour of another (e.g. a transcription factor activates or represses a gene). Higher-order interactions, while more subtle, may be important for determining the function of networks. Here, the authors systematically expand a simp...

UMP2 calculations with aug-cc-pVTZ basis set used to analyse intermolecular interactions in X3C···PH2Y···ClY (X = H, CH3; Y CN, NC) complexes constructed via halogen bond and single-electron pnicogen two discovered minima the potential energy surface. The first presents short P?C distances and, all cases, high interaction energies compared second one that shows long a typical weak interaction. ...

Hemoglobin cross-linked as a bis(isophthalamide) of the epsilon-amino groups of lysine 82 of each beta-subunit binds and releases oxygen with a Hill coefficient indicative of cooperative oxygen binding (typically approximately 2.0). However, connecting two such cross-linked tetramers with a relatively short covalent linkage produces cross-linked bis-tetramers that bind oxygen with Hill coeffici...

We study a statistical-mechanical model of the binding of DNA-bending proteins to the double helix including applied tension and binding cooperativity effects. Intrinsic cooperativity of binding sharpens force-extension curves and causes enhancement of fluctuation of extension and protein occupation. This model also allows us to estimate the intrinsic cooperativity in experiments by measuring t...

The inhibition of Escherichia coli d-3-phosphoglycerate dehydrogenase by l-serine is positively cooperative with a Hill coefficient of approximately 2, whereas the binding of the inhibitor, l-serine, to the apoenzyme displays positive cooperativity in the binding of the first two serine molecules and negative cooperativity in the binding of the last two serine molecules. An earlier report demon...

Understanding the nature of H-bonding interactions is essential to modern sciences, such as biology, chemistry, and physics. Using density functional theory calculations, herein, we have identified two unique types existing in a single sheet mixed water–hydroxyl phase on close-packed metal surfaces, sharp contrast conventional H-bonds liquid water ices. Interestingly, shallow show reduced elect...

Abstract We show that Fano interference can be realized in a macroscopic microwave cavity coupled to spin ensemble at room temperature. Via formalism developed from the linearized Jaynes-Cummings model of electromagnonics, we generalized emerges photon–magnon interaction low cooperativity. In this regime, reflectivity approximates scattering cross-section derived Fano-Anderson model. Although a...