Unraveling subunit cooperativity in homotetrameric HCN2 channels.

ABSTRACT: 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 in homotetrameric HCN2 pacemaker channels. The individual steps in the model were characterized by Gibbs free energies for the equilibria and activation energies, specifying the affinity of the binding sites and the transition rates, respectively. Moreover, cooperative free energies were calculated for each binding step in both the closed and the open channel. We show that the cooperativity sequence

SUBMITTER: Benndorf K 

PROVIDER: S-EPMC3491687 | biostudies-literature | 2012 Nov

REPOSITORIES: biostudies-literature