Cyanobacteria, that appeared earlier in evolution contain membrane-associated phycobilisomes (see e.g., (Neilson and Durnford 2010)) with a pigment-to-protein ratio that is substantially lower (~1:5) although still higher than for the core complex. For recent studies of
EET in/from phycobilisomes in vitro and in vivo the reader is referred to Tian et al. (Tian et al. 2011, 2012). The PFT�� cell line present review will focus on light harvesting in plants. The thylakoid membrane in plants is divided into grana, which are composed of stacks of membrane disks, and stroma lamellae, which connect the various grana in the choroplast Blasticidin S molecular weight (Mustardy and Garab 2003; Shimoni et al. 2005; Mustardy et al. 2008; Daum et al. 2010; Kouril et al. 2011). PSII is located in
the grana (Andersson and Anderson 1980) whereas PSI is mainly present in the stroma lamellae (together with the ATP synthase). The thylakoid membrane is flexible and dynamic and able to respond to changes in environmental conditions by changing both composition and organization of the PSII supercomplexes (Anderson et al. 2008; click here Chuartzman et al. 2008; Goral et al. 2010). It has been shown that part of the grana membrane contains PSII arrays that consist of supercomplexes with different antenna sizes, but the abundance of the arrays seems to depend on the composition of PSII which for instance depends on the species analyzed and on the growth conditions (Boekema et al. 2000; Kouril et al.; Daum et al. 2010; Kirchhoff et al. 2007; Methocarbamol Kouril et al. 2012; Kiss et al. 2008) (Kereiche et al. 2010; Kovacs et al. 2006; de Bianchi et al. 2008). Only part of the PSII supercomplexes is embedded in these regular arrays, while another part is less organized. It is not exactly clear yet what the role of the arrays and the other parts is. But it is known that reorganizations in both arrays and other parts take place as a function
of light quality and intensity (Wientjes et al. 2013; Kouril et al. 2012; Jahns and Holzwarth 2012; Betterle et al. 2009). In Fig. 2, a model of a plant PSII supercomplex is shown. It is composed of a PSII core together with the gene products of genes Lhcb1-6 in a well-defined arrangement. The largest supercomplexes contain a dimeric core, four LHCII (encoded by Lhcb1-3) trimers, two strongly bound (S) and two moderately strongly bound (M), and two monomeric copies each of CP29 (Lhcb4), CP26 (Lhcb5), and CP24 (Lhcb6). Supercomplexes of different sizes can be isolated (Caffarri et al. 2009), which is probably partly due to the solubilization process but it is also known that a sub-population of smaller supercomplexes is also observed in high light plants (see e.g., (Daum et al. 2010; Kouril et al. 2012)). Fig. 2 Model of the PSII supercomplex C2S2M2 from higher plants. Top-view for the stromal side on a C2S2M2 supercomplex from A. thaliana.