bio d103 lecture 2 -- signaling II: specificity of molecular interactions, roles of covalent and non-covalent interactions, and protein domains in signaling

what does specificity of interactions cause

discrete signaling outcomes

how is binding of a signaling molecule to a specific target determined

molecular conformation of the molecules + associated multiple weak force interactions

specificity

ability of molecule to stably bind to one target in preference to another

what do high specificity interactions need

molecular complementarity → e.g. the shape and chemical properties of the binding sites must be complementary to each other

affinity

relative strength of molecular interaction, usually defined as dissociation constant (Kd)

ideal binding characteristics

non-covalent, weak, dynamic, and can reach equilibrium → why? because this enables reversible binding of the molecules (common in biological systems)

examples of molecular con