Surface and spectroscopic properties of photosystem II core complex at the nitrogen/water interface

Judith Gallant, Hugo Lavoie, Alain Tessier, Gaétan Munger, Roger M. Leblanc, Christian Salesse

Research output: Contribution to journalArticle

19 Scopus citations

Abstract

We have studied surface and spectroscopic properties of Photosystem II core complex (PS II CC) for the first time in monolayers at the nitrogen/water interface. A new instrument was thus specially built to perform absorption and fluorescence spectroscopic measurements directly at the nitrogen/water interface. The effect of initial surface density, incubation time, and compression speed have been studied. When PS II CC was spread at an initial surface pressure of 5.7 mN/m and immediately compressed at a speed of 40 nm2/molecule·min, it retained its native spectroscopic characteristics. Even though a slower speed of compression (10 nm2/molecule·min) produced more homogeneous films, the absorption maxima suffered a blue shift, indicating denaturation of PS II CC. Compression at a speed of 80 nm2/molecule·min produced aggregates of intact PS II CC as indicated by ΔV-A isotherms, absorption spectra, and fluorescence micrographs. We also conclude that spreading of PS II CC at an initial surface pressure of 0.6 mN/m followed by a 30 min incubation time is inadequate to maintain PS II CC surface and spectral properties. Indeed, π-A and ΔV-A isotherms measured in that condition showed transitions which suggested that PS II CC underwent physical changes during compression. Moreover, absorption and fluorescence maxima were blue shifted, indicating that PS II CC is denatured under that condition.

Original languageEnglish (US)
Pages (from-to)3954-3963
Number of pages10
JournalLangmuir
Volume14
Issue number14
DOIs
StatePublished - Jul 7 1998

ASJC Scopus subject areas

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

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