Morphology and structural properties of pH-responsive amphiphilic peptides

Jeanne N. Shera, Daisuke Takahashi, Alvaro I. Herrera, Om Prakash, Xiuzhi Susan Sun

Research output: Contribution to journalArticlepeer-review


Protein nanomaterials at the peptide level have shown great potential for medical applications. Peptides change their morphological conformation because of changes in self-assembly properties when they are exposed to changes in solvent composition or pH. Two 15-residue peptide sequences, KhK (KKKFLIVIGSIIKKK) and Alternating Kh (KFLKKIVKIGKKSII), were designed for the purpose of determining the role of peptide sequence on solution morphology and conformation. KhK solutions exhibited a random coil to helical transition when solvent conditions were changed from water to a trifluorethanol/water solution at acidic pH. Alternating Kh solutions, however, demonstrated primarily random coil character under similar solvent and pH conditions as determined by circular dichroism spectroscopy and 2D- 1H- 1H nuclear magnetic resonance spectroscopy. At basic pH, circular dichroism spectroscopy and nuclear magnetic resonance spectroscopy analysis demonstrated that random coil character increased at basic pH for KhK, whereas Alternating Kh exhibited an increase in β-sheet character. Further analysis by transmission electron microscopy showed marked differences in the peptide solution morphology. Peptide particle aggregation and fiber formation were significantly affected by solvent composition and pH values for both peptide sequences.

Original languageEnglish
Pages (from-to)7981-7987
Number of pages7
JournalJournal of nanoscience and nanotechnology
Issue number12
Publication statusPublished - Dec 2010
Externally publishedYes

All Science Journal Classification (ASJC) codes

  • Bioengineering
  • General Chemistry
  • Biomedical Engineering
  • General Materials Science
  • Condensed Matter Physics


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