Protein assembly and heat stability in developing thylakoid membranes during greening

Abstract

The development of the thylakoid membrane was studied during illumination of dark-grown barley seedlings by using biochemical methods, and Fourier transform infrared and spin label electron paramagnetic resonance spectroscopic techniques. Correlated, gross changes in the secondary structure of membrane proteins, conformation, composition, and dynamics of lipid acyl chains, SDS͞PAGE pattern, and thermally induced structural alterations show that greening is accompanied with the reorganization of membrane protein assemblies and the protein-lipid interface. Changes in overall membrane fluidity and noncovalent proteinlipid interactions are not monotonic, despite the monotonic accumulation of chlorophyll, LHCII [light-harvesting chlorophyll a͞b-binding (polypeptides) associated with photosystem II] apoproteins, and 18:3 fatty acids that follow a similar time course with highest rates between 12-24 h of greening. The 18:3 fatty acid content increases 2.8-fold during greening. This appears to both compensate for lipid immobilization by membrane proteins and facilitate packing of larger protein assemblies. The increase in the amount of protein-solvating immobile lipids, which reaches a maximum at 12 h, is caused by 40% decrease in the membranous mean diameter of protein assemblies at constant protein͞lipid mass ratio. Alterations in the SDS͞PAGE pattern are most significant between 6 -24 h. The size of membrane protein assemblies increases Ϸ4.5-fold over the 12-48-h period, likely caused by the 2-fold gain in LHCII apoproteins. The thermal stability of thylakoid membrane proteins increases monotonically, as detected by an increasing temperature of partial protein unfolding during greening. Our data suggest that a structural coupling between major protein and lipid components develops during greening. This protein-lipid interaction is required for the development and protection of thylakoid membrane protein assemblies.barley (Hordeum vulgare) ͉ FTIR ͉ photosynthesis ͉ protein-lipid interaction ͉ spin label EPR

Functional significance of the lipid-protein interface in photosynthetic membranes

“…By definition, greening is characterized by chlorophyll accumulation, which is generally used as the parameter to describe the time course of this process [123]. Recently, we studied greening in darkgrown barley seedlings, using biochemical methods, and FTIR and SL EPR spectroscopic techniques [124].…”

Three-Dimensional Visualization of the Tubular-Lamellar Transformation of the Internal Plastid Membrane Network during Runner Bean Chloroplast Biogenesis

“…It involves changes in gene expression together with the transcriptional and translational control of both nuclear and plastid genes. These genes can be regulated by anterograde and retrograde signals, the synthesis of necessary lipids and pigments, the import and routing of the nucleusencoded proteins into plastids, protein-lipid interactions, the insertion of proteins into the plastid membranes, and the assembly into functional complexes (Vothknecht and Westhoff, 2001;Baena-González and Aro, 2002;Kota et al, 2002;Stern et al, 2004;López-Juez, 2007;Waters and Langdale, 2009;Solymosi and Schoefs, 2010;Adam et al, 2011;Pogson and Albrecht, 2011;Ling et al, 2012;Jarvis and López-Juez, 2013;Lyska et al, 2013;Belcher et al, 2015;Börner et al, 2015;Dall'Osto et al, 2015;Ling and Jarvis, 2015;Rast et al, 2015;Sun and Zerges, 2015;Yang et al, 2015). Chloroplast biogenesis is highly integrated with cell and plant development, especially with photomorphogenesis (Pogson et al, 2015), and is controlled by cellular and organismal regulatory mechanisms such as the ubiquitin-proteasome system (Jarvis and López-Juez, 2013).…”

Essential Role of VIPP1 in Chloroplast Envelope Maintenance in Arabidopsis

“…The biogenesis of thylakoids is apparently a complex process that involves the synthesis and maintenance of pigments, proteins, and lipids (Herrmann, 1999;Vothknecht and Westhoff, 2001). It is also affected by environment (e.g., light, temperature, and nutrients) and by organ development (Tzinas et al, 1987;Monge et al, 1993;Kota et al, 2002). Despite such complexity, several important factors involved in thylakoid formation have been proposed, including VESICLE-INDUCING PROTEIN IN PLASTIDS1 (VIPP1), THYLAKOID FORMATION1 (THF1), CHLOROPLAST SECRETION-ASSOCIATED RAS1 (CPSAR1), and FtsH (Kroll et al, 2001;Sakamoto et al, 2003;Wang et al, 2004;Garcia et al, 2010).…”