Influence of the Nonprotein Amino Acid Mimosine in PeptideConformational Propensities from Novel Amber Force FieldParameters

Mimosine is a nonprotein amino acid derived from plantsknown for its ability to bind to divalent and trivalent metal cations suchas Zn2+,Ni2+,Fe2+,orAl3+. This results in interesting antimicrobial andanticancer properties, which make mimosine a promising candidate fortherapeutic applications. One possibility is to incorporate mimosine intosynthetic short peptide drugs. However, how this amino acid affects thepeptide structure is not well understood, reducing our ability to designeffective therapeutic compounds. In this work, we used computersimulations to understand this question. Wefirst built parameters for themimosine residue to be used in combination with two classical forcefields of the Amber family. Then, we used atomistic molecular dynamicssimulations with the resulting parameter sets to evaluate the influence ofmimosine in the structural propensities for this amino acid. We comparedthe results of these simulations with homologous peptides, wheremimosine is replaced by either phenylalanine or tyrosine. We found that the strong dipole in mimosine induces a preference forconformations where the amino acid rings are stacked over more extended conformations. We validated our results using quantummechanical calculations, which provide a robust foundation for the outcome of our classical simulations

Automated summary

This study investigates the influence of the nonprotein amino acid mimosine on peptide structure using computer simulations. The results show that mimosine prefers a stacked conformation of the amino acid rings. Quantum mechanical calculations validate the findings of the simulations.