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Effects of salt wash on the structure of the prolamellar body iembrane and the membrane binding of NADPH–protochlorophyllide oxidoreductase
Author(s) -
Widell–Wigge Anna,
Selstam Eva
Publication year - 1990
Publication title -
physiologia plantarum
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.351
H-Index - 146
eISSN - 1399-3054
pISSN - 0031-9317
DOI - 10.1111/j.1399-3054.1990.tb09042.x
Subject(s) - protochlorophyllide , isoelectric point , absorbance , membrane , biochemistry , divalent , pigment , chemistry , oxidoreductase , membrane protein , isoelectric focusing , chromatography , biology , enzyme , organic chemistry
NADPn–protochlorophyllide oxidoreductase (EC 1.6.99.1; PCR) is the major protein component of the prolamellar body (PLB) membrane of the etioplast. The interaction between the pigment–protein complex of PCR and the membrane lipids is of importance for the induction and maintenance of the regularly branched PLB structure. The isoelectric point of the PLB surface and the impact of salt treatment on the PLB structure, the PCR absorbance properties and the association of PCR to the membrane, have been studied in isolated fractions of PLBs from dark–grown wheat ( Triticum aestivum L. cv. Starke 11). We conclude that the PLB membrane has its isoelectric point at pH 4.5. which is similar to that of other plastid membranes. The PLB membrane and the pigment–protein complex of PCR are both affected by salt treatment. Concentrations below 50 mM MgCl 2 , or 250 m M KCI tend to stabilize the regularly branched strueture. while higher concentrations of both mono– and divalent cations lead to disintegration of the membrane and shifts towards shorter wave–lengths of the in vivo absorbance spectra of protoehlorophyllide. PCR. the dominant PLB protein, however, seems to be intimately associated with the membrane lipids and is not washed off the membrane by repeated salt treatment.