Surface properties of "jellyfish": Langmuir monolayer and langmuir-blodgett film studies of recombinant aequorin

Wang Chengshan, Miodrag Micic, Mark Ensor, Sylvia Daunert, Roger M. Leblanc

Research output: Contribution to journalArticle

6 Scopus citations

Abstract

In this paper, we studied the surface properties of recombinant aequorin at the air-water interface. Using the Langmuir monolayer technique, the surface properties of aequorin were studied, including the surface pressure and surface potential-area isotherms, compression-decompression cycles, and stability on Trizma Base (Tris/HCl) buffer at pH 7.6. The results showed that aequorin formed a stable Langmuir monolayer and the surface pressure-area isotherms were dependent on both pH and ionic strength. At a pH higher or lower than 7.6, the limiting molecular area decreased. The circular dichroism (CD) spectra of aequorin in aqueous solutions explained this result: when the pH was higher than 7.6, the α-helix conformation changed to unordered structures, whereas at a pH lower than 7.6, the α-helix conformation changed to β-sheet. The addition of calcium chloride to the Tris/HCl buffer subphase (pH 7.6) caused an increase of the limiting molecular area of the aequorin Langmuir monolayer. The fluorescence spectra of a Langmuir-Blodgett (LB) film of aequorin in the presence of calcium chloride indicated that the aequorin transformed to the apoaequorin.

Original languageEnglish (US)
Pages (from-to)7602-7607
Number of pages6
JournalLangmuir
Volume23
Issue number14
DOIs
StatePublished - Jul 3 2007

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ASJC Scopus subject areas

  • Materials Science(all)
  • Condensed Matter Physics
  • Surfaces and Interfaces
  • Spectroscopy
  • Electrochemistry

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