On the interaction between the imidazolium cation and aromatic amino acids. A computational study
Ana A Rodríguez-Sanz1, Enrique M Cabaleiro-Lago, Jesús Rodríguez-Otero
1Departamento de Química Física, Facultade de Ciencias, Universidade de Santiago de Compostela, Campus de Lugo. Avda. Alfonso X El Sabio s/n 27002, Lugo, Spain. caba.lago@usc.es.
Organic & Biomolecular Chemistry
|June 26, 2015
Summary
Computational studies reveal imidazolium cations interact with aromatic amino acids phenylalanine, tyrosine, and tryptophan via stacked structures. Histidine shows unique zwitterionic interactions, highlighting diverse binding mechanisms in these biomolecular complexes.
Area of Science:
- Computational Chemistry
- Biomolecular Interactions
- Physical Chemistry
Background:
- Aromatic amino acids (phenylalanine, tyrosine, tryptophan, histidine) are crucial biological building blocks.
- Imidazolium cations are prevalent in ionic liquids and biological systems.
- Understanding cation-aromatic amino acid interactions is key to molecular recognition and drug design.
Purpose of the Study:
- To investigate the complexation behavior between the imidazolium cation and four aromatic amino acids.
- To elucidate the structural preferences and interaction energies of these complexes.
- To compare the binding modes of phenylalanine, tyrosine, tryptophan, and histidine with the imidazolium cation.
Main Methods:
- High-level computational methods, specifically MP2.X level of theory, were employed.
- Complexation energies were calculated to quantify interaction strengths.
- Analysis of non-covalent interactions, including hydrogen bonding, cation-π contacts, and electrostatic/inductive forces, was performed.
Main Results:
- Phenylalanine, tyrosine, and tryptophan form stable complexes with the imidazolium cation, primarily through stacked arrangements involving cation-π interactions and hydrogen bonds.
- Zwitterionic forms of these amino acids also yield comparably stable complexes.
- Histidine exhibits distinct behavior, favoring zwitterionic forms with strong hydrogen bonding, lacking cation-π interactions, and showing the highest complexation stability among the studied amino acids.
Conclusions:
- Imidazolium cation interactions with phenylalanine, tyrosine, and tryptophan are versatile, allowing for both stacked and zwitterionic structures.
- Histidine's interaction with the imidazolium cation is predominantly through hydrogen bonding in its zwitterionic form, demonstrating a unique binding motif.
- The findings provide insights into the nuanced interplay between charged species and aromatic residues in biological and chemical systems.
More Related Videos
05:57Author Spotlight: In Silico Creation and Impact of Carbonylated Amino Acids on Protein Structure and Function
Published on: April 26, 2024
977
11:04Ion Mobility-Mass Spectrometry Techniques for Determining the Structure and Mechanisms of Metal Ion Recognition and Redox Activity of Metal Binding Oligopeptides
Published on: September 7, 2019
10.0K
Related Concept Videos
01:25Basicity of Heterocyclic Aromatic Amines
7.2K
Heterocyclic amines, where the N atom is a part of an alicyclic system, are similar in basicity to alkylamines. Interestingly, the heterocyclic amine having a nitrogen atom as part of an aromatic ring has much less basicity than its corresponding alicyclic counterpart. For this reason, as presented in Figure 1, piperidine (pKb = 2.8) is significantly more basic than pyridine (pKb = 8.8).
7.2K
01:18Basicity of Aromatic Amines
8.4K
The basicity of aromatic amines is much weaker than that of aliphatic amines due to the involvement of the lone pair of electrons over the N atom in resonance with the aryl rings. Generally, the electron-donating ability of any substituents on the aryl ring of aromatic amines increases the basicity of the amine by increasing electron density, and hence the availability of lone pair on the nitrogen. On the other hand, electron-withdrawing functional groups on the aryl ring of amines decrease the...
8.4K
01:19Structure of Amines
3.4K
The hybridized nitrogen atom in amines possesses a lone pair of electrons and is bound to three substituents with a bond angle of around 108°, which is less than the tetrahedral angle of 109.5°. However, the C–N–H bond angle is slightly larger at 112°, with a carbon–nitrogen bond length of 147 pm. This carbon–nitrogen bond length of of amines is longer than the carbon–oxygen bond of alcohols (143 pm) but shorter than alkanes’ carbon–carbon bond (154 pm). These aspects are...
3.4K
01:23Aldehydes and Ketones with Amines: Imine Formation Mechanism
10.0K
Imine formation involves the addition of carbonyl compounds to a primary amine. It begins with the generation of carbinolamine through a series of steps involving an initial nucleophilic attack and then several proton transfer reactions. The second part includes the elimination of water, as a leaving group, to give the imine.
Imines are formed under mildly acidic conditions. A pH of 4.5 is ideal for the reaction.
If the pH is low or the solution is too acidic, the reaction slows down in the...
Imines are formed under mildly acidic conditions. A pH of 4.5 is ideal for the reaction.
If the pH is low or the solution is too acidic, the reaction slows down in the...
10.0K
01:11Aryldiazonium Salts to Azo Dyes: Diazo Coupling
4.2K
The reaction of weakly electrophilic aryldiazonium (also called arenediazonium) salts with highly activated aromatic compounds leads to the formation of products with an —N=N— link, called an azo linkage. This reaction, presented in Figure 1, is known as diazo coupling and occurs without the loss of the nitrogen atoms of the aryldiazonium salt. Highly activated aromatic compounds such as phenols or arylamines favor the diazo coupling reaction. The coupling generally occurs at the para...
4.2K
01:371° Amines to Diazonium or Aryldiazonium Salts: Diazotization with NaNO2 Mechanism
5.3K
Nitrous acid is a relatively weak and unstable acid prepared in situ by the reaction of sodium nitrite and cold, dilute hydrochloric acid. In an acidic solution, the nitrous acid undergoes protonation when it loses water to form a nitrosonium ion—an electrophile. Nitrous acid reacts with primary amines to give diazonium salts. The reaction is called diazotization of primary amines.
5.3K