Changes in the abundance of individual apoproteins of light-harvesting chlorophyll a b-protein complexes of Photosystem I and II with growth irradiance in the marine chlorophyte Dunaliella tertiolecta

Assaf Sukenik, John Bennett, Paul Falkowski

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71 Scopus citations

Abstract

The marine chlorophyte Dunaliella tertiolecta responds to increased growth irradiance (in the range 70-1900 μmol quanta·m-2·s-1) by decreasing its cellular content of reaction centers I and II by as much as 75% (Sukenik, A., Bennett, J. and Falkowski, P.G. (1987) Biochim. Biophys. Acta 891, 205-215). We have used Western blot techniques and antibodies raised against homologous pea proteins to examine changes in the concentration of the corresponding light-harvesting antenna complexes, LHC I and LHC II. Three LHC I apoproteins (22, 27.5 and 32 kDa) and four LHC II apoproteins (24.5, 28.5, 30 and 31 kDa) were detected. With increasing growth irradiance, the 22 and 27.5 kDa LHC I apoproteins and the 30 and 31 kDa LHC II apoproteins declined in parallel with RC I and RC II. In contrast, the 32 kDa LHC I apoprotein remained equally abundant per cell at all irradiances and the 28.5 kDa II apoprotein declined by only 30%. The fact that purified LHC II extracted from high-light cells (1200 μmol quanta·m-2·s-1) contained a lower chlorophyll (Chl) b content than LHC II purified from low-light cells (70 μmol quanta·m-2·s-1) suggests that the LHC II apoproteins differ in their capacity to bind Chl b. We conclude that photo-adaptive changes in pigment composition in D. tertiolecta are brought about not only by changes in the total abundance of LHC I and LHC II, but also by differential accumulation of individual LHC I and LHC II apoproteins. A simple procedure for detecting irradiance-dependent changes in the light-harvesting apparatus of other green algae is presented.

Original languageEnglish
Pages (from-to)206-215
Number of pages10
JournalBiochimica et Biophysica Acta - Bioenergetics
Volume932
Issue numberC
DOIs
StatePublished - 1 Jan 1988
Externally publishedYes

Keywords

  • (D. tertiolecta)
  • Light harvesting complex apoprotein
  • Light level
  • Reaction center

ASJC Scopus subject areas

  • Biophysics
  • Biochemistry
  • Cell Biology

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