Number of chlorophyll a per Photosystem II reaction centre

Value 185 Copies/reaction center
Organism Cyanobacteria Gloeobacter violaceus
Reference John A. Raven Functional evolution of photochemical energy transformations in oxygen-producing organisms, Functional Plant Biology, 2009, 36, 505–515 p.511 right column top paragraph
Primary Source Koyama K, Suzuki H, Noguchi T, Akimoto S, Tsuchiya T, Mimuro M. Oxygen evolution in the thylakoid-lacking cyanobacterium Gloeobacter violaceus PCC 7421. Biochim Biophys Acta. 2008 Apr1777(4):369-78PubMed ID18298941
Method Primary source: In this study, researchers compared the amino acid sequences of three extrinsic proteins involved in cyanobacterial oxygen-evolving processes, and investigated interactions between the PS II subunits in G. violaceus and Synechocystis as a control. In order to characterize PS II (including the Mn-cluster), they examined oxygen-evolving activity, thermoluminescence, delayed luminescence at 1.6 s after the flash and delayed fluorescence on the nanosecond time scale at - 196 °C.
Comments Oxygen flash yield data on Gloeobacter grown at low irradiances (Koyama et al. 2008) suggest 185 chlorophyll a per PSII reaction centre, so the PSI : PSII ratio is only 1.06, and the density of the photosystems in low-light cells is 34 nmol/m^2 for PSII and 36 nmol/m^2 for PSI. See BNID 105048,105049
Entered by Uri M
ID 105046