Lipid‐polymorphism of plant thylakoid membranes. Enhanced non‐bilayer lipid phases associated with increased membrane permeability

Abstract

Earlier experiments, using 31P‐NMR and time‐resolved merocyanine fluorescence spectroscopy, have shown that isolated intact, fully functional plant thylakoid membranes, in addition to the bilayer phase, contain three non‐bilayer (or non‐lamellar) lipid phases. It has also been shown that the lipid polymorphism of thylakoid membranes can be characterized by remarkable plasticity, i.e. by significant variations in 31P‐NMR signatures. However, changes in the lipid‐phase behaviour of thylakoids could not be assigned to changes in the overall membrane organization and the photosynthetic activity, as tested by circular dichroism and 77 K fluorescence emission spectroscopy and the magnitude of the variable fluorescence of photosystem II, which all showed only marginal variations. In this work, we investigated in more detail the temporal stability of the different lipid phases by recording 31P‐NMR spectra on isolated thylakoid membranes that were suspended in sorbitol‐ or NaCl‐based media. We observed, at 5°C during 8 h in the dark, substantial gradual enhancement of the isotropic lipid phases and diminishment of the bilayer phase in the sorbitol‐based medium. These changes compared well with the gradually increasing membrane permeability, as testified by the gradual acceleration of the decay of flash‐induced electrochromic absorption changes and characteristic changes in the kinetics of fast chlorophyll a‐fluorescence transients; all variations were much less pronounced in the NaCl‐based medium. These observations suggest that non‐bilayer lipids and non‐lamellar lipid phases play significant roles in the structural dynamics and functional plasticity of thylakoid membranes.

Modulation of non-bilayer lipid phases and the structure and functions of thylakoid membranes: effects on the water-soluble enzyme violaxanthin de-epoxidase

“…3). In our earlier study we have shown close correlation between the gradually enhanced isotropic lipid phases, accompanied by shifts of the 31 P-NMR isotropic peaks to higher field positions, and the increased permeability of thylakoid membranes 31 .…”

“…2b and Supplementary Fig. 2; see also 31 ); (2) the magnitude of the pH-induced shifts Figure 1. Measured and spectrally deconvoluted and fitted 31 P-NMR spectra of isolated spinach thylakoid membranes.…”

“…This could be recognized despite the time-dependent drifts of the peaks in the same direction (cf. 31 ). Reversibility of the changes induced by increasing the temperature from 5 to 15 °C can be clearly recognized in the isotropic region ( Fig.…”

Photosynthesis—European Congress on Photosynthesis Research

“…A number of articles treat regulatory aspects of photosystem II (Shevela et al ), the plastoquinone pool (Borisova‐Mubarakshina et al ), cytochrome c (Bernal‐Bayard et al ), redox regulation (Nikkanen et al ), photoacclimation (Hu et al ) and photorespiration (García‐Caledrón et al ). The growing interest in structural aspects is shown by articles on the dynamics of the thylakoid membrane (Solovchenko et al , Konert et al , Ughy et al ) and of specific proteins (Carius et al , Vojta and Fulgosi ), protein complexes (Kuthanová Trsková et al , Fedorov et al ) and the antenna (Albanese et al , Kuthanová Trsková et al 2019). An important tool for photosynthesis research is variable chlorophyll fluorescence, which is used to study photosystem II in isolated form, in thylakoid membranes as well as in vivo.…”

“…and theoretical and experimental consideration on the water-splitting complex (Capone et al 2019, Yamaguchi et al 2019, Chatterjee et al 2019) and photosystem I (Santabarbara et al 2019a) to more integrated aspects of photosynthesis research (Buezo et al 2019, Hamdani et al 2019, Ptushenko and Ptushenko 2019, Hernández-Prieto et al 2019, Krieger-Liszkay et al 2019). A number of articles treat regulatory aspects of photosystem II (Shevela et al 2019), the plastoquinone pool (Borisova-Mubarakshina et al 2019), cytochrome c (Bernal-Bayard et al 2019), redox regulation (Nikkanen et al 2019), photoacclimation (Hu et al 2019) and photorespiration (García-Caledrón et al 2019).The growing interest in structural aspects is shown by articles on the dynamics of the thylakoid membrane(Solovchenko et al 2019, Konert et al 2019, Ughy et al 2019 and of specific proteins (Carius et al 2019, Vojta and Fulgosi 2019), protein complexes (Kuthanová Trsková et al 2019, Fedorov et al 2019) and the antenna (Albanese et al 2019, Kuthanová…”