Synechococcus elongatus

Table III reports structural statistics relative to the solution structures of iron-sulfur proteins available from the Protein Data Bank (118). The lowest percentage of residue assignment occurs for oxidized Synechococcus elongatus Fd (119). The highest percentage of proton assignment is instead obtained for oxidized E. halophila HiPIP, with a value as high as 95% (120). A close figure was also obtained for the reduced protein (94%). In the latter case, such high values are obtained also thanks to the availability of labeled...

Zouni, A., H. T. Witt, J. Kern, P. Fromme, N. Krauss, W. Saenger and P. Orth (2001) Crystal structure of photosystem II from Synechococcus elongatus at 3.8 A resolution. Nature, 409 739-743... 

Fig. 2.125. HPLC chromatograms generated at 440 nm. Pure cultures (a) Synechococcus elongatus, (b) 2 micron picosphere , (c) Cyclotella choctawatcheena. Phytoplankton field communities (d) Twin Key Basin, (e) Rabbit Key Basin, (f) Sandy Key Basin, ft = /1-carotene, Z = zeaxanthin, a = chlorophyll-a, N = myxoxanthophyll, E = echinenone, c,/c2 = chlorophylls-Cj/c2, F = fucoxanthin, Col = unknown carotenol, Cone = unknown carotenone, D = diadinoxan-thin, P = peridin. Reprinted with permission from J. W. Louda et al. [283].

The solution structure of the 87-residue cytochrome cg from the thermophilic cyanobacterium Synechococcus elongatus (optimal temperature for photosynthetic activity = 57 °C) was determined by multidimensional NMR spectroscopy and molecular dynamics calculations and exhibited the overall topology of class I c cytochromes with four a-helices and a small antiparallel /1-sheet near Met58, one of the axial haem ligands. ... 

Photosystem I (PS I) in the cyanobacterium Synechococcus elongatus is the first system of this type for which the structure has been solved in atomic detail. Although the bacterial photosystem differs slightly from the systems in higher plants, the structure provides valuable hints about the course of the light reactions in photosynthesis (see p. 128). The functioning of the photosystem is discussed in greater detail on p. 130. 

Figure 1 Introduction of clostridial hydrogenase into cells of Synechococcus elongatus by electroporation.

A Zouni, L Lneberg, P Fromme, WD Schubert, W Saenger and FIT Witt (1998) Characterization of single crystals of photosystem II from the thermophilic cyanobacterium Synechococcus elongatus. In G Garab (ed) Photosynthesis Mechanisms and Effects, Vol II, 925-928. Kluwer N Adir (1998) Crystallization of the reaction center of photosystem II. ibid, 945-948 A Zouni, R Jordan, E Schlodder, P Fromme and FIT Witt (2000) First photosystem II crystals capable of water oxidation. Biochim Biophys Acta 1457 103-105... 

Fig. 3. (A) Arrangement of pigment molecules and electron-transfer cofactors in the PS-1 reaction center, viewed along the membrane plane. Numerical values are distances in A. (B) stereo view ofthe same pigment and cofactor molecules as in (A). Both figures adapted from Schubert, Klukas, KrauB, Saenger, Fromme and Witt (A) (1995) Present state of the crystal structure analysis of photosystem I at 4.5 A resolution. In P Mathis (ed) Photosynthesis From Light to Biosphere, II 5. Kluwer (B) (1997) Photosystem I of Synechococcus elongatus at 4 A resolution comprehensive structure analysis. J Mol Biol 272 p 756. Also see Color Plate 10 for a color rendition ofthe electron-density map of (A).

W-D Schubert, 0 Klukas, N Krau, W Saenger, P Fromme and HT Witt (1997) Three-dimensional crystals of Photosystem I of Synechococcus elongatus at4 resolution Comparative structure analysis. J Mol Biol 272 741-769... 

The PS-I core complex (CC 1) used by these workers for crystallization and X-ray crystallographic analysis was purified from Synechococcus elongatus and found to exist in the trimeric form. Each PS-1 monomer unit consisted of the major PsaA and PsaB polypeptides, plus several other smaller subunits, and included a full complement of electron-transfer cofactors, P700, (A), Ao, A, FeS-X and FeS-A/B. It was also known to contain 90 Chl-a molecules per P700. The amount of core-antenna chlorophyll-a in this preparation was comparable to that found in the core complexes of spinach and other cyanobacteria. To simplify the designation, the core-antenna Chi a will now be abbreviated as CA-Chl a. ... 

In addition to the membrane-anchored enzymes that support anaerobic respiration, bacteria express a number of functionally, and structurally, distinct nitrate reductases related by the presence of an Mo[MGD]2 containing active site. PFV has demonstrated tunnel-diode behaviour from two of these the periplasmic Rhodobacter sphaeroides NapAB and the assimilatory Synechococcus elongatus NarB. In both cases preferential binding of nitrate to the Mo , over Mo , oxidation state provides an explanation for the catalytic voltammetry and this may prove to be a conserved feature of the catalytic cycle in these enzymes. 

It has been shown that the enantioselectivity of the reduction of ketones by the photosynthetic cyanobacterium Synechococcus elongatus PCC 7942 is regulated by light. In the case of the ketone (28), the enantioselectivity is reduced by over 50% in the absence of light (Nakamura and Yamanaka, Chapter 5). It was also shown that a known photosynthesis inhibitor decreases both the chemical and enantiomeric purities of the products, which suggests that physiological changes on irradiation alfect the enzymatic activity of cyanobacteria. 

KaiA N-terminal domain PCC7942 Synechococcus elongatus S. elongatus) NMR Williams et al 2002 lm2e... 

Williams, S.B., Vakonakis, I., Golden, S.S., and LiWang, A.C. (2002). Structure and function from the circadian clock protein KaiA of Synechococcus elongatus a potential clock input mechanism Proc. Natl. Acad. Sci. USA 99, 15357-15362. 

Ye, S., Vakonakis, I., loerger, T.R., LiWang, A.C., and Sacchettini, J.C. (2004). Crystal structure of circadian clock protein KaiA from Synechococcus elongatus. J. Biol. Chem. 279, 20511-20518. 

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