Arginine: I. Interactions of Its Guanidinium Moiety with Branched Aliphatic Side Chains.

ABSTRACT: The guanidine moiety of arginine side chains in proteins is often close to branched aliphatic side chains. We used the dispersion-corrected ωB97X-D density functional to calculate the interaction energy between the models of Arg and Leu side chains. We found that, in the lowest energy planar-like structures, the amino groups of methylguanidinium ion─our model of Arg side chains, and the methyl groups of 2-methylbutane─our model of leucine or isoleucine side chains, approach each other very closely. In these pairs, the methyl groups of Leu act as bases, donating electrons to the Arg side chains. The shortest distance between hydrogen atoms on different monomers is smaller than the sum of their van der Waals radii (2.2-2.4 Å). The shortest distance between a nitrogen atom of Arg and a carbon

SUBMITTER: Ng CM 

PROVIDER: S-EPMC12302063 | biostudies-literature | 2025 Jul

REPOSITORIES: biostudies-literature