allostate

An allostate refers to a specific conformational state of a protein that is distinct from its resting or basal state. Proteins, particularly enzymes and receptors, often exist in multiple conformational states. These states can differ in their three-dimensional structure, which in turn affects their activity, binding properties, and interactions with other molecules.

The concept of allostate is closely related to allostery, which describes the phenomenon where the binding of a ligand (an allosteric effector) at one site on a protein influences its activity or binding at another site. This influence is mediated by a change in the protein's conformation, leading to the adoption of a different allostate. For example, an enzyme might have an allosteric site where an activator molecule binds, causing the enzyme to shift into an active allostate. Conversely, an inhibitor binding to an allosteric site could induce an inactive allostate.

Proteins can exist in several different allostates, each with unique characteristics. The transition between these states is often driven by the binding of small molecules, ions, or other proteins, as well as by changes in the cellular environment such as pH or temperature. Understanding the different allostates of a protein is crucial for comprehending its biological function, regulation, and for the design of drugs that target specific protein conformations.