Heterotropic transition

Heterotropic transition Heterotropic interactions may be transmitted to the regulatory sites by the tower helices and by changes at the subunit contacts. The simultaneous binding of allosteric activator and allosteric inhibitor gives rise to a structure intermediate between the T and the R structures. The heterotropic effect is exerted throughout the subunit interface contacts. 

A cyclophane possesses a hydrophobic cavity suitable for complexation of nonpolar organic guests. Several heterotropic allosteric systems based on cavity formation induced by complexation with transition metal cations were reported. The idea is generally similar to metal-induced... 

The model, therefore, accounts for both homotropic and heterotropic interactions and for their interdependence. No particular assumptions has been, or need be, made about the strncmre of the specific sites or about the stmcture of the protein, except that it is a symmetrically bonded oligomer, the symmetry of which is conserved when it undergoes a transition from one to another state. 

---