Structure binding cavity

Members of the different SERM families bind to the ligand-binding domain (LBD) of the ER, whose particular crystal structure has been revealed for estradiol and for raloxifene (Brzozowski et al. 1997). Once inserted into the binding cavity, estradiol makes direct hydrogen bonds bewteen its A-ring and... 

Because of this photoisomerisation, structural changes occur within the confines of the binding cavity, which in turn produce changes in the opsin and the attached cell-membrane protein. This results in functional changes to the cell membrane, culminating in generation of a signal impulse which is sent to the brain. 

Because the stability constant of its complex with potassium is much greater than that with sodium, valinomycin is a relatively specific potassium ionophore. In contrast, the mushroom peptide antamanide has a binding cavity of a different geometry and shows a strong preference for sodium ions.388,390 The structure of the Na+-antamanide complex is also shown in Fig. 8-22B. The Streptomyces polyether antibiotic monensin (Fig. 8-22D),389,391 a popular additive to animal feeds, is also an ionophore. However, its mode of action, which involves disruption of Golgi functions, is uncertain 392... 

Structure of a crystalline fatty acidbinding protein from liver with two molecules of bound oleate (dark rods). The lower molecule is more deeply embedded in the protein and more tightly bound than the second molecule, which is closer to the outer surface of the protein. Semitransparent grey marks the solvent-accessible surface of the binding cavity. An unknown molecule, perhaps butanoic acid (as modeled), binds also at top of the protein. See Thompson et al.n Courtesy of Leonard Banaszak. 

The size and shape of the binding cavity that they define and their rigidity or flexibility are determined by the nature of the structural subunits making up the branches of the graphical representations. Their overall shape and appearance has also led to the coining of a number of so-called trivial names that refer to a particular aspect of the structure. Proposals have been made to name and define different types of macrocyclic ligands and molecular receptors [2.12]. Without being ex-... 

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