In cell-free extracts from low-aeration suspensions of Rhodospirillum rubrum strain G-9, bacteriochlorophyll a was distributed in two bands after rate-zone sedimentation in sucrose density gradients. From the physicochemical properties of these fractions, it was concluded that the upper band consisted of small membrane fragments, whereas the major band was composed of fragmented vesicular intra...

Jutta Thiemann and W olfgang Barz Institut für Biochemie und Biotechnologie der Pflanzen, Westfälische Wilhelms-Universität, Hindenburgplatz 55, D-48143 Münster, Bundesrepublik Deutschland Dedicated to Professor Rolf Wiermann on the occasion o f his 60th birthday Z. Naturforsch. 49c, 791-801 (1994); received May 30/July 11, 1994 Chenopodium rubrum, Photoautotrophic Cell Cultures, Herbicide Resi...

Six light-harvesting-2 complexes (LH2) from genetically modified strains of the purple photosynthetic bacterium Rhodobacter (Rb.) sphaeroides were studied using static and ultrafast optical methods and resonance Raman spectroscopy. These strains were engineered to incorporate carotenoids for which the number of conjugated groups (N = NC═C + NC═O) varies from 9 to 15. The Rb. sphaeroides strains...

An additional component in the purified core light-harvesting complex (LH1) from wild-type purple photosynthetic bacterium Rhodospirillum rubrum has been identified as an oxidized species of alpha-polypeptide by MALDI-TOF mass spectrometry. This component appears as a slightly earlier-eluting peak in the RP-HPLC chromatogram compared with the authentic alpha-polypeptide. The oxidation site has ...

Three photosynthetic complexes, light-harvesting complex 2 (LH2), light-harvesting complex 1 (LH1), and the reaction centre-light-harvesting complex 1 photounit (RC-LH1), were purified from a single species of a purple bacterium, Rhodobacter sphaeroides, and reconstituted into two-dimensional (2-D) crystals. Vesicular 2-D crystals of LH1 and RC-LH1 were imaged in negative stain and projection m...

Blue and green sunlight become available for photosynthetic energy conversion through the light-harvesting (LH) function of carotenoids, which involves transfer of carotenoid singlet excited states to nearby (bacterio)chlorophylls (BChls). The excited-state manifold of carotenoids usually is described in terms of two singlet states, S(1) and S(2), of which only the latter can be populated from ...

The relationship between light-induced absorbance changes and photophosphorylation has been studied in extracts of the photosynthetic bacterium Rhodosfiirillum rubrum purified by partition in dextran-methyl cellulose mixtures. In these preparations infrared light induces absorbance changes in the visible region of the spectrum which are modified by the addition of reductants required for photop...

Spheroplasts of the photosynthetic bacterium Rhodospirillum rubrum were prepared from cultures grown in either the presence or absence of light. Cells were converted into spheroplasts by using lysozyme and Versene and fixed in a sucrose-veronal-acetate buffer mixture containing osmium tetroxide. Some preparations were shadow-cast and examined whole; others were embedded in Epon 812 and sectione...

Ribulose-1,5-bisphosphate carboxylase/oxygenase (RubisCO) catalyzes the first step of CO(2) fixation in the Calvin-Benson-Bassham (CBB) cycle. Besides its function in fixing CO(2) to support photoautotrophic growth, the CBB cycle is also important under photoheterotrophic growth conditions in purple nonsulfur photosynthetic bacteria. It has been assumed that the poor photoheterotrophic growth o...