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Ion pair formation involving methylated lysine side chains: a theoretical study
Proteins
|April 1, 1994
Summary
Posttranslational lysine methylation, a protein modification, weakens ionic interactions. This study used computational methods to model how methylation affects lysine
Area of Science:
- Biochemistry
- Computational Chemistry
- Molecular Biology
Background:
- Lysine residues in proteins can undergo posttranslational methylation, acquiring one to three methyl groups.
- This modification is found in numerous proteins and can alter protein function.
Purpose of the Study:
- To evaluate the impact of lysine methylation on ion-pair formation.
- To understand how varying degrees of methylation affect interactions with charged molecules.
Main Methods:
- Employed semiempirical (AM1) and ab initio (6-31G*) molecular orbital calculations.
- Modeled interactions between methylated amines (as lysine analogs) and carboxylate/phosphate groups.
Main Results:
- Interaction energy between methylated lysine analogs and counterions decreases as the number of methyl groups increases.
- Calculations including a solvent reaction field provided realistic interaction energies in aqueous solution.
Conclusions:
- Increasing methylation of lysine residues weakens their ionic interactions with negatively charged groups.
- This weakening of ionic interactions is a contributing factor to the diverse physiological roles of lysine methylation.