Light-harvesting complex photosystem

Ruban, A.V., Robert, B., and Horton, P. 1995. Resonance Raman spectroscopy of photosystem B light-harvesting complex of green plants. A comparison of trimeric and aggregated states. Biochemistry 34 2333-2337. 

A, Absorption chi, chlorophyll car, carotenoid EET, excitonic energy transfer EF, exoplasmic fracture face EM, electron microscopy FWHM, full width at half maximum lEF, Isoelectric Focusing, LD, linear dichroism LHC, light harvesting complex PAGE, polyacrylamide gel electophoresis PF, protoplasmic fracture face PS, photosystem RC, reaction centre SDS, sodium dodecyl sulphate SSTT, single step transfer time. 

Kargul, J., Nield, J., Barber, J. (2003) Three -dimensional reconstruction of a light-harvesting Complex I-Photosystem I (LHCI-PSI) supercomplex from the green alga Chlamydomonas rein-hardtii., J. Biol. Chem. 278, 16,135-16,141. 

Figure 5-19. Schematic representation of reactions occurring at the photosystems and certain electron transfer components, emphasizing the vectorial or unidirectional flows developed in the thylakoids of a chloroplast. Outwardly directed election movements occur in the two photosystems (PS I and PS II), where the election donors are on the inner side of the membrane and the election acceptors are on the outer side. Light-harvesting complexes (LHC) act as antennae for these photosystems. The plastoquinone pool (PQ) and the Cyt b(f complex occur in the membrane, whereas plastocyanin (PC) occurs on the lumen side and ferredoxin-NADP+ oxidoreductase (FNR), which catalyzes electron flow from ferredoxin (FD) to NADP+, occurs on the stromal side of the thylakoids. Protons (H+) are produced in the lumen by the oxidation of water and also are transported into the lumen accompanying electron (e ) movement along the electron transfer chain.

P. E. Jensen, M. Gilpin, J. Knoetzel, and H.V. Scheller. 2000. The PSI-K subunit of photosystem I is involved in the interaction between light-harvesting complex I and the photosystem I reaction center core J. Biol. Chem. 275 24701-24708. (PubMed)... 

Photosystem II splits water (the Hill reaction). Its reaction centre absorbs maximally at 680 run, and its is found mostly on grana, associated with light-harvesting complex II. It also contains more chlorophyll-b than PSI. 

Characterization of the Light-Harvesting Complex Proteins of the Photosystems in Control and Chi b-less Mutant... 

The present work illustrates in some detail the result of a unique mutation, one that impaired the biosynthesis of Chi b and resulted in a truncated Chi antenna size for the photosystems [Tanaka et al. 1998]. In the present Chi Mess mutant, PSII contained 93 Chi a molecules and PSI contained 246 Chi a molecules (Table 3). These antenna sizes are significantly larger than the PSII-core and PSl-core antennae, suggesting that Chi b may not be absolutely essential for the assembly of all Chi a-b light-harvesting complexes (see also [Ghirardi et al. 1986]). This was especially true for PSI which, in the Chi Mess mutant, had a Chi antenna size almost as large as that of the control (Table 3). It may be concluded that the Chi Mless mutation can be overcome by a nearly quantitative substitution of Chi b with Chi a in the Chi antenna of PSI, and by a partial substitution by Chi a in the antenna of PSII. 

Harrison MA and Melis A. (1992). Organization and stability of polypeptides associated with the chlorophyll a-b light-harvesting complex of photosystem-II. Plant Cell Physiol. 33, 627-637. 

Thomber JP, Peter GF, Chitnis PR, Nechushtai R and Vainstein A. (1988). The light-harvesting complex of photosystem II of higher plants. In Stevens SE Jr, Bryant DA (eds), Light-energy Transduction in Photosynthesis Higher Plant and Bacterial Models, pp. 137-154 The American Society of Plant Physiologists, Rockville, Maryland. 

Fig. 12. Simple models of various photosystems (A) purple bacteria, (B) green bacteria, (C) cyanobacteria and red algae, (D) bro n algae and (E) green plants. RC=reaction center FCPA=fucoxanthin-chlorophyll-protein assembly LHC=light-harvesting complex PS ll=photosystem II PS l=photosystem I. See text for discussion.

The outermost Chi a/b binding proteins, called LHC II (light-harvesting complex associated with photosystem II). 

Chapter 12 Photosystem-ll Light-Harvesting Complexes II. C. The Carotenoid Lutein... 

B. Gene Coding of Photosystem-I Light-Harvesting Complexes.450... 

In Vivo Organization of Light-Harvesting Complexes in the Photosystem-I Reaction Center.456... 

---