title: Importance of trimer-trimer interactions for the native state of the plant light-harvesting complex II.
abstract: Aggregates and solubilized trimers of LHCII were characterized by circular dichroism (CD), linear dichroism and time-resolved fluorescence spectroscopy and compared with thylakoid membranes in order to evaluate the native state of LHCII in vivo. It was found that the CD spectra of lamellar aggregates closely resemble those of unstacked thylakoid membranes whereas the spectra of trimers solubilized in n-dodecyl-beta,D-maltoside, n-octyl-beta,D-glucopyranoside, or Triton X-100 were drastically different in the Soret region. Thylakoid membranes or LHCII aggregates solubilized with detergent exhibited CD spectra similar to the isolated trimers. Solubilization of LHCII was accompanied by profound changes in the linear dichroism and increase in fluorescence lifetime. These data support the notion that lamellar aggregates of LHCII retain the native organization of LHCII in the thylakoid membranes. The results indicate that the supramolecular organization of LHCII, most likely due to specific trimer-trimer contacts, has significant impact on the pigment interactions in the complexes.
authors.affiliation: Institute of Plant Biology, Biological Research Center, Hungarian Academy of Sciences, H-6726 Szeged, Hungary.
authors.forename: Petar H
authors.initials: PH
authors.lastname: Lambrev
authors.forename: Zsuzsanna
authors.initials: Z
authors.lastname: Várkonyi
authors.forename: Sashka
authors.initials: S
authors.lastname: Krumova
authors.forename: László
authors.initials: L
authors.lastname: Kovács
authors.forename: Yuliya
authors.initials: Y
authors.lastname: Miloslavina
authors.forename: Alfred R
authors.initials: AR
authors.lastname: Holzwarth
authors.forename: Gyozo
authors.initials: G
authors.lastname: Garab
mesh_terms: D002942:Circular Dichroism; D003902:Detergents / Q000494:pharmacology; D005960:Glucosides / Q000494:pharmacology; D045342:Light-Harvesting Protein Complexes / Q000737:chemistry* / Q000302:isolation & purification; D017830:Octoxynol / Q000494:pharmacology; D045332:Photosystem II Protein Complex / Q000737:chemistry* / Q000302:isolation & purification; D012995:Solubility / Q000187:drug effects; D012997:Solvents / Q000494:pharmacology; D013050:Spectrometry, Fluorescence; D020524:Thylakoids / Q000737:chemistry
chemical_list: D003902:Detergents; D005960:Glucosides; D045342:Light-Harvesting Protein Complexes; D045332:Photosystem II Protein Complex; D012997:Solvents; C018619:octyl-beta-D-glucoside; C040358:dodecyl maltoside; D017830:Octoxynol