Structurally flexible macro-organization of the pigment-protein complexes of the diatom Phaeodactylum tricornutum

Szabó, M; Lepetit, B; Goss, R; Wilhelm, C; Mustárdy, L; Garab, G

Structurally flexible macro-organization of the pigment-protein complexes of the diatom Phaeodactylum tricornutum

Szabó, M

Lepetit, B Goss, R Wilhelm, C Mustárdy, L Garab, G

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Publication Type:: Journal Article
Citation:: Photosynthesis Research, 2008, 95 (2-3), pp. 237 - 245
Issue Date:: 2008-02-01

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Field	Value	Language
dc.contributor.author	Szabó, M https://orcid.org/0000-0001-6235-2894	en_US
dc.contributor.author	Lepetit, B	en_US
dc.contributor.author	Goss, R	en_US
dc.contributor.author	Wilhelm, C	en_US
dc.contributor.author	Mustárdy, L	en_US
dc.contributor.author	Garab, G	en_US
dc.date.available	2007-09-07	en_US
dc.date.issued	2008-02-01	en_US
dc.identifier.citation	Photosynthesis Research, 2008, 95 (2-3), pp. 237 - 245	en_US
dc.identifier.issn	0166-8595	en_US
dc.identifier.uri	http://hdl.handle.net/10453/14898
dc.description.abstract	By means of circular dichroism (CD) spectroscopy, we have characterized the organization of the photosynthetic complexes of the diatom Phaeodactylum tricornutum at different levels of structural complexity: in intact cells, isolated thylakoid membranes and purified fucoxanthin chlorophyll protein (FCP) complexes. We found that the CD spectrum of whole cells was dominated by a large band at (+)698 nm, accompanied by a long tail from differential scattering, features typical for psi-type (polymerization or salt-induced) CD. The CD spectrum additionally contained intense (-)679 nm, (+)445 nm and (-)470 nm bands, which were also present in isolated thylakoid membranes and FCPs. While the latter two bands were evidently produced by excitonic interactions, the nature of the (-)679 nm band remained unclear. Electrochromic absorbance changes also revealed the existence of a CD-silent long-wavelength (∼545 nm) absorbing fucoxanthin molecule with very high sensitivity to the transmembrane electrical field. In intact cells the main CD band at (+)698 nm appeared to be associated with the multilamellar organization of the thylakoid membranes. It was sensitive to the osmotic pressure and was selectively diminished at elevated temperatures and was capable of undergoing light-induced reversible changes. In isolated thylakoid membranes, the psi-type CD band, which was lost during the isolation procedure, could be partially restored by addition of Mg-ions, along with the maximum quantum yield and the non-photochemical quenching of singlet excited chlorophyll a, measured by fluorescence transients. © 2007 Springer Science+Business Media B.V.	en_US
dc.relation.ispartof	Photosynthesis Research	en_US
dc.relation.isbasedon	10.1007/s11120-007-9252-3	en_US
dc.subject.classification	Plant Biology & Botany	en_US
dc.subject.mesh	Diatoms	en_US
dc.subject.mesh	Proteins	en_US
dc.subject.mesh	Spectrometry, Fluorescence	en_US
dc.subject.mesh	Circular Dichroism	en_US
dc.subject.mesh	Molecular Conformation	en_US
dc.subject.mesh	Pigments, Biological	en_US
dc.title	Structurally flexible macro-organization of the pigment-protein complexes of the diatom Phaeodactylum tricornutum	en_US
dc.type	Journal Article
utslib.citation.volume	2-3	en_US
utslib.citation.volume	95	en_US
utslib.for	0607 Plant Biology	en_US
utslib.for	0601 Biochemistry and Cell Biology	en_US
utslib.for	0604 Genetics	en_US
pubs.embargo.period	Not known	en_US
pubs.organisational-group	/University of Technology Sydney
pubs.organisational-group	/University of Technology Sydney/Faculty of Science
utslib.copyright.status	open_access
pubs.issue	2-3	en_US
pubs.publication-status	Published	en_US
pubs.volume	95	en_US

Abstract:

By means of circular dichroism (CD) spectroscopy, we have characterized the organization of the photosynthetic complexes of the diatom Phaeodactylum tricornutum at different levels of structural complexity: in intact cells, isolated thylakoid membranes and purified fucoxanthin chlorophyll protein (FCP) complexes. We found that the CD spectrum of whole cells was dominated by a large band at (+)698 nm, accompanied by a long tail from differential scattering, features typical for psi-type (polymerization or salt-induced) CD. The CD spectrum additionally contained intense (-)679 nm, (+)445 nm and (-)470 nm bands, which were also present in isolated thylakoid membranes and FCPs. While the latter two bands were evidently produced by excitonic interactions, the nature of the (-)679 nm band remained unclear. Electrochromic absorbance changes also revealed the existence of a CD-silent long-wavelength (∼545 nm) absorbing fucoxanthin molecule with very high sensitivity to the transmembrane electrical field. In intact cells the main CD band at (+)698 nm appeared to be associated with the multilamellar organization of the thylakoid membranes. It was sensitive to the osmotic pressure and was selectively diminished at elevated temperatures and was capable of undergoing light-induced reversible changes. In isolated thylakoid membranes, the psi-type CD band, which was lost during the isolation procedure, could be partially restored by addition of Mg-ions, along with the maximum quantum yield and the non-photochemical quenching of singlet excited chlorophyll a, measured by fluorescence transients. © 2007 Springer Science+Business Media B.V.

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http://hdl.handle.net/10453/14898