IGFBP-4 does not bind ECM as it lacks ECM-binding sites equivalent to those found in IGFBP-2, -3 or -5 (Forbes et al, 2012) and therefore only has one IGF release mechanism.
The binding site is equivalent to an antibody with respect to the surface area.
Most notably, there is a single binding site for the substrate ATP, with the protein symmetry-related site (equivalent to the second ATP site in the bacterial enzyme) now able to bind the allosteric activator bicarbonate.
On the other side of the spectrum, when networks are not sparse, and the spontaneous gain rate of binding sites is relatively equivalent to their loss rate, selecting on a specific pathway function does not affect regulatory complexity.
In both cases, the binding site is not inside the channel cavity and thus there are six equivalent binding sites due to the six-fold symmetry of the p7 channel.
These pairs or families of proteins may thus possess equivalent binding sites with respect to DISC1, and it would be worthwhile to tease apart common and variable binding regions.
This result clearly shows that presenting multiple equivalent binding sites to the binding partner has a measurably positive effect on the effective affinity of the individual interaction site.
The two agonist binding sites were assumed to be equivalent and independent [37] and the interval durations at all three concentrations were fitted together by using a C↔AC↔A2C↔A2O kinetic model (A = agonist) that had four rate constants as free parameters: single-site association (k+, scaled by [A]), single-site dissociation (k−), ko, and kc.
This model applies to the adsorption of solute with a homogeneous distribution of binding sites and equivalent adsorption energies including no interaction between the molecules of the solute and a point is reached where maximum adsorption takes place and finally equilibrium is attained (Ogata et al. 2014).
Unlike the human region, it also lacks consensus Sp1, Sp3 and Oct 1 binding sites at equivalent positions.
