Biomaterial Database

Cation-pi interactions involving aromatic amino acids. 2007

Dennis A Dougherty

Division of Chemistry and Chemical Engineering, California Institute of Technology, Pasadena, CA 91125, USA. dadougherty@caltech.edu

The cation-pi interaction is a general, strong, noncovalent binding force that is used throughout nature. The side chains of the aromatic amino acids [phenylalanine (Phe), tyrosine (Tyr), and tryptophan (Trp)] provide a surface of negative electrostatic potential than can bind to a wide range of cations through a predominantly electrostatic interaction. In this brief overview, the fundamental nature of the cation-pi interaction will be described, relying on fundamental, gas phase studies of the effect. Then, several examples of cation-pi interactions involving aromatic amino acids will be described. These include contributions to protein secondary structure, in which Phe/Tyr/Trp...lysine (Lys)/arginine interactions are common. We will also describe several examples of protein-ligand interactions that make use of cation-pi interactions. We will place special emphasis on the binding of quaternary ammonium ions, such as trimethylated Lys and the neurotransmitter acetylcholine.

UI	MeSH Term	Description	Entries
D008958	Models, Molecular	Models used experimentally or theoretically to study molecular shape, electronic properties, or interactions; includes analogous molecules, computer-generated graphics, and mechanical structures.	Molecular Models,Model, Molecular,Molecular Model
D011487	Protein Conformation	The characteristic 3-dimensional shape of a protein, including the secondary, supersecondary (motifs), tertiary (domains) and quaternary structure of the peptide chain. PROTEIN STRUCTURE, QUATERNARY describes the conformation assumed by multimeric proteins (aggregates of more than one polypeptide chain).	Conformation, Protein,Conformations, Protein,Protein Conformations
D011506	Proteins	Linear POLYPEPTIDES that are synthesized on RIBOSOMES and may be further modified, crosslinked, cleaved, or assembled into complex proteins with several subunits. The specific sequence of AMINO ACIDS determines the shape the polypeptide will take, during PROTEIN FOLDING, and the function of the protein.	Gene Products, Protein,Gene Proteins,Protein,Protein Gene Products,Proteins, Gene
D002412	Cations	Positively charged atoms, radicals or groups of atoms which travel to the cathode or negative pole during electrolysis.	Cation
D006657	Histones	Small chromosomal proteins (approx 12-20 kD) possessing an open, unfolded structure and attached to the DNA in cell nuclei by ionic linkages. Classification into the various types (designated histone I, histone II, etc.) is based on the relative amounts of arginine and lysine in each.	Histone,Histone H1,Histone H1(s),Histone H2a,Histone H2b,Histone H3,Histone H3.3,Histone H4,Histone H5,Histone H7
D017433	Protein Structure, Secondary	The level of protein structure in which regular hydrogen-bond interactions within contiguous stretches of polypeptide chain give rise to ALPHA-HELICES; BETA-STRANDS (which align to form BETA-SHEETS), or other types of coils. This is the first folding level of protein conformation.	Secondary Protein Structure,Protein Structures, Secondary,Secondary Protein Structures,Structure, Secondary Protein,Structures, Secondary Protein
D018377	Neurotransmitter Agents	Substances used for their pharmacological actions on any aspect of neurotransmitter systems. Neurotransmitter agents include agonists, antagonists, degradation inhibitors, uptake inhibitors, depleters, precursors, and modulators of receptor function.	Nerve Transmitter Substance,Neurohormone,Neurohumor,Neurotransmitter Agent,Nerve Transmitter Substances,Neurohormones,Neurohumors,Neuromodulator,Neuromodulators,Neuroregulator,Neuroregulators,Neurotransmitter,Neurotransmitters,Substances, Nerve Transmitter,Transmitter Substances, Nerve,Substance, Nerve Transmitter,Transmitter Substance, Nerve
D024322	Amino Acids, Aromatic	Amino acids containing an aromatic side chain.	Aromatic Amino Acids,Amino Acid, Aromatic,Aromatic Amino Acid