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2001 (1)
1986 (2)
1Author    Andre BucheRequires cookie*
 Title    Wavelength Shifts Correlation between Near Infrared and Ultraviolet Regions of the LHII Bacteriochlorophyll Spectrum from Ectothiorhodospira sp  
 Abstract    Bacteriochlorophyll a has a maximum at 258 nm previously related to the ring E ester system interacting with the Ji-system of the macrocycle. In this work, we compared the effect o f lauryldimethylamine-N-oxide (LD AO) and alkaline pH on both the near infrared and the ultraviolet region of the LHII spectrum from E ctothiorhodospira sp. While LDAO induces only a shift of the 850 nm band arising from the Q y transition of the bacteriochlorophyll a, alkaline pH also causes a concomitant and reversible 10-nm shift from 258 to 248 nm. Both shifts have similar apparent pKs (12.3 and 12.6, respectively). Interestingly, the presence of NaCl reduces these pKs values to 11.4 and 11.7. 
  Reference    Z. Naturforsch. 56c, 363 (2001); received D ecem ber 11 2000/January 23 2001 
  Published    2001 
  Keywords    Bacteriochlorophyll, Ectothiorhodospira, Light-Harvesting Complex 
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 TEI-XML for    default:Reihe_C/56/ZNC-2001-56c-0363.pdf 
 Identifier    ZNC-2001-56c-0363 
 Volume    56 
2Author    R. Steiner, B. Kalumenos, H. ScheerRequires cookie*
 Title    The Photosynthetic Apparatus of Ectothiorhodospira halochloris 3. Effect of Proteolytic Digestion on the Photoactivity  
 Abstract    of Rhodopseudomonas viridis and Ectothiorhodospira halochloris were treated with proteinase K. The photochemical activity (light minus dark difference spectra) were compared to the polypeptide composition (SDS-polyacrylamide gel analysis). In E. halo­ chloris, difference bands appear at 806 (+), 838 (+) and 854 nm (-) . All three decrease in intensity upon incubation with proteinase K., but this decrease is much slower than the proteolysis of both the reaction center and antenna related polypeptides. Photochemical activity remains high as long as a small part of the RC and two lower molecular weight polypeptides M* (22.0 kDa) and B* (15.3 kDa) are present. The M subunit is the most stable polypeptide in the RC of Rp. viridis too, and the photochemical activity is related to the remainder of this and to the one newly formed polypeptide (15.3 kDa), but doesn't show the typical absorption shift of the antenna (B 800/1020 —» B 800/960). The results are discussed quantitatively a containing organisms. 
  Reference    Z. Naturforsch. 41c, 873—880 (1986); received July 17 1986 
  Published    1986 
  Keywords    Bacterial Photosynthesis, Ectothiorhodospira, Reaction Center, Proteolysis, Difference Spectro­ scopy Photosynthetic membranes 
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 TEI-XML for    default:Reihe_C/41/ZNC-1986-41c-0873.pdf 
 Identifier    ZNC-1986-41c-0873 
 Volume    41 
3Author    R. Steiner, A. A. Ngerhofer+, H. ScheerRequires cookie*
 Title    The Photosynthetic Apparatus of Ectothiorhodospira halochloris 2. Accessibility of the Membrane Polypeptides to Partial Proteolysis and Antenna Polypeptide Assignments to Specific Chromophores  
 Abstract    E. halochloris thylakoids and spheroplasts were treated with trypsin, thermolysin or proteinase K to determ ine which proteins are exposed at the different m embrane surfaces. B ased on SD S polyacrylamide analysis, all 9 polypeptides are exposed on the cytoplasm ic side. O nly one (28 k D a) is accessible from the periplasmic side. This polypeptide is generally isolated as the H-subunit o f the reaction centers of photosynthetic bacteria, but is in the case o f E. halochloris rather isolated with the antenna (B 800/1020) (Steiner and Scheer, Biochim . Biophys. A cta 807, 278, 1983). Proteolysis is accom panied by a shift of the absorption band at longest w avelengths from 1020 to 960 nm (B 800/960), which upon standing is shifted further to 680 nm ("B " 800/680). The spectral changes are similar to the ones reported earlier for treatm ent with acid, and are also inducible with urea. The correlation o f SD S-P A G E and absorption spectroscopy show s, that the chrom ophores absorbing at 1020 nm are transformed sim ultaneously with the degradation o f the 6.5 kD a (— a) polypeptide. 
  Reference    Z. Naturforsch. 41c, 571 (1986); received January 9 1986 
  Published    1986 
  Keywords    Bacterial Photosynthesis, Ectothiorhodospira, M embrane T opology, A ntenna Polypeptides, F luorescence, Circular D ichroism, Energy Transfer 
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 TEI-XML for    default:Reihe_C/41/ZNC-1986-41c-0571.pdf 
 Identifier    ZNC-1986-41c-0571 
 Volume    41