Arginine-aromatic interactions and their effects on arginine-induced solubilization of aromatic solutes and suppression of protein aggregation

Dhawal Shah, Jianguo Li, Abdul Rajjak Shaikh, Raj Rajagopalan

Research output: Contribution to journalArticlepeer-review

33 Citations (Scopus)

Abstract

We examine the interaction of aromatic residues of proteins with arginine, an additive commonly used to suppress protein aggregation, using experiments and molecular dynamics simulations. An aromatic-rich peptide, FFYTP (a segment of insulin), and lysozyme and insulin are used as model systems. Mass spectrometry shows that arginine increases the solubility of FFYTP by binding to the peptide, with the simulations revealing the predominant association of arginine to be with the aromatic residues. The calculations further show a positive preferential interaction coefficient, Γ XP, contrary to conventional thinking that positive Γ XP's indicate aggregation rather than suppression of aggregation. Simulations with lysozyme and insulin also show arginine's preference for aromatic residues, in addition to acidic residues. We use these observations and earlier results reported by us and others to discuss the possible implications of arginine's interactions with aromatic residues on the solubilization of aromatic moieties and proteins. Our results also highlight the fact that explanations based purely on Γ XP, which measures average affinity of an additive to a protein, could obscure or misinterpret the underlying molecular mechanisms behind additive-induced suppression of protein aggregation.

Original languageEnglish
Pages (from-to)223-231
Number of pages9
JournalBiotechnology Progress
Volume28
Issue number1
DOIs
Publication statusPublished - Jan 1 2012

Keywords

  • Arginine
  • Preferential interaction coefficient
  • Protein aggregation

ASJC Scopus subject areas

  • Biotechnology

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