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Protein–Ligand Interactions: General Description

  1. Michael F Dunn

Published Online: 19 APR 2010

DOI: 10.1002/9780470015902.a0001340.pub2

eLS

eLS

How to Cite

Dunn, M. F. 2010. Protein–Ligand Interactions: General Description. eLS. .

Author Information

  1. University of California, Riverside, California, USA

Publication History

  1. Published Online: 19 APR 2010

Abstract

Protein–ligand interactions are fundamental to almost all processes occuring in living organisms. Ligand-mediated signal transmission via molecular complementarity is essential to all life processes; these chemical interactions comprise biological recognition at the molecular level. The evolution of protein function is dependent in part on the development of highly specific sites designed to bind small-molecule ligands with affinities tuned to the needs of the cell. Cooperativity in ligand binding is critically important to the regulation of competing biological functions. Regulation of cellular processes via cooperative protein–ligand interactions occurs through molecular mechanisms involving protein conformational transitions among low- and high-affinity states. Consequently, ligand-binding interactions are used to switch proteins among states of different function. Examples ranging from dioxygen transport to gene expression are presented. The structures of protein–ligand complexes at atomic resolution make possible the design of small-molecule drugs for the treatment of disease.

Key Concepts:

  • Molecular recognition via protein–ligand interactions is of fundamental importance to most processes occurring within living organisms.

  • Transmission of signals via molecular complementarity is essential to all life processes.

  • The evolution of protein function includes the development of highly specific sites for the binding of ligands with affinities tailored to meet the needs of biological function.

  • Cooperativity in ligand binding plays an important role in the regulation of biological function.

  • Cooperativity in ligand binding is linked to conformational change in the protein.

  • Well-defined mathematical expressions based on the stoichiometry of the binding equilibrium provide a means for quantifying ligand-binding interactions.

  • The equilibrium constants of ligand–macromolecule interactions provide a thermodynamic measure of the strength of the interaction.

  • The atomic resolution structures of ligand complexes provide a chemical basis for understanding protein–ligand interactions and these structures are often used as the basis for the design of small-molecule drugs for the treatment of disease.

Keywords:

  • cooperativity;
  • ligand;
  • dissociation constant;
  • biological recognition;
  • specificity;
  • drugs;
  • signal transmission;
  • binding;
  • bonding forces