Probing the smallest functional unit of the reaction center of <i>Rhodospirillum rubrum</i> G‐9 with proteinases

Wiemken, V.; Bachofen, Reinhard

doi:10.1016/0014-5793(84)80063-0

Cited by 18 publications

(6 citation statements)

References 9 publications

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“…are insignificant at least as far as the methods applied are concerned. This result would be in line with earlier studies on Bchl proteins including R C from several bacteria, which showed remarkably little effects of proteolysis on their spectra and function (Wiemken and Bachofen, 1984;Steiner et al, 1986).…”

Section: Homogeneity Of the Preparationsupporting

confidence: 91%

CHEMICALLY MODIFIED PHOTOSYNTHETIC BACTERIAL REACTION CENTERS: CIRCULAR DICHROISM, RAMAN RESONANCE, LOW TEMPERATURE ABSORPTION, FLUORESCENCE AND ODMR SPECTRA AND POLYPEPTIDE COMPOSITION OF BOROHYDRIDE TREATED REACTION CENTERS FROM Rhodobacter sphaeroides R26

Beese¹,

Steiner²,

Scheer³

et al. 1988

Photochem & Photobiology

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Abstract-Reaction centers from Rhodobacter sphaeroides have been modified by treatment with sodium borohydride similar to the original procedure [Ditson el al., Biochim. Biophys. Acta 766, 623 (1984)], and investigated spectroscopically and by gel electrophoresis.(1) Low temperature (1.2 K) absorption, fluorescence, absorption-and fluorescence-detected ODMR, and microwave-induced singlet-triplet absorption difference spectra (MIA) suggest that the treatment produces a spectroscopically homogeneous preparation with one of the 'additional' bacteriochlorophylls being removed. The modification does not alter the zero field splitting parameters of the primary donor triplet (TP870).(2) From the circular dichroism and Raman resonance spectra in the 1500-1800 c m -' region, the removed pigment is assigned to Bchl,, e.g. the "extra" Bchl on the "inactive" M-branch. (3) A strong coupling among all pigment molecules is deduced from the circular dichroism spectra, because pronounced band-shifts and/or intensity changes occur in the spectral components assigned to all pigments. This is supported by distinct differences among the MIA spectra of untreated and modified reaction centers, as well as by Raman resonance. (4) The modification is accompanied by partial proteolytic cleavage of the M-subunit. The preparation is thus spectroscopically homogeneous, hut biochemically heterogenous.

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Section: Homogeneity Of the Preparationsupporting

confidence: 91%

CHEMICALLY MODIFIED PHOTOSYNTHETIC BACTERIAL REACTION CENTERS: CIRCULAR DICHROISM, RAMAN RESONANCE, LOW TEMPERATURE ABSORPTION, FLUORESCENCE AND ODMR SPECTRA AND POLYPEPTIDE COMPOSITION OF BOROHYDRIDE TREATED REACTION CENTERS FROM Rhodobacter sphaeroides R26

Beese¹,

Steiner²,

Scheer³

et al. 1988

Photochem & Photobiology

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“…Fur-the~or~ the high degree of o~~tation of the Chls in vivo f3] strongly suggests a binding of the pigments to anisotropic regions of the protein. In addition these pigments are well shielded from the aqueous environment and are not affected by protease treatments which clip external segments of the protein [27, 29,30] thus su~esting that they are buried in a hydrophobic core such as the one provided by cr-helices. Hydrophobic stretches, which probably correspond to a-helical segments, have been observed in the primary structure of several antenna [25,31,32] and reaction center f33] polypeptides.…”

Section: Pebs Lettersmentioning

confidence: 99%

Transmembrane orientation of α‐helices and the organization of chlorophylls in photosynthetic pigment‐protein complexes

Breton¹,

Nabedryk²

1984

FEBS Letters

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UV CD and IR spectra of the water‐soluble bacteriochlorophyll‐protein antenna isolated from Prosthecochloris aestuarii indicate that about 50% of the protein is in a β‐sheet conformation while for the dominant antenna complexes isolated from bacteria (B800‐850) and from green plants (LHC), the α‐helix (45%) is more abundant than the β‐sheet (~ 10%) conformation. Furthermore, IR dichroism studies show that the α‐helical segments of a large variety of intrinsic membrane Chl‐protein complexes (antenna and reaction centers) are tilted on the average at 30–35° away from the membrane normal. The observation that in these complexes the Chl planes are also tilted at about the same angle suggests that the transmembrane orientation of the α‐helices determines the positioning of the Chl molecules in photosynthetic membranes.

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“…The L and M subunits are known to bind the photosynthetic pigments, since in Rhodopseudomonas sphaeroides, which is now called Rhodobacter sphaeroides (Imhoff et al, 1984), and Rhodospirillum (Rs.) rubrum the H subunit can be removed, and the residual complex remains photochemically active (Feher and Okamura, 1978;Wiemken and Bachofen, 1984). The reaction centres from several purple photosynthetic bacteria, e.g.…”

Section: Introductionmentioning

confidence: 99%

The ‘light’ and ‘medium’ subunits of the photosynthetic reaction centre from Rhodopseudomonas viridis : isolation of the genes, nucleotide and amino acid sequence

et al. 1986

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The ‘light’ (L) and the ‘medium’ (M) subunits of the photosynthetic reaction centre from Rhodopseudomonas viridis were isolated and their amino‐terminal sequences, as well as the sequences of several chymotryptic peptides, determined. Rps. viridis DNA was cloned in the Escherichia coli plasmid pBR322. Mixed oligonucleotide probes derived from the amino acid sequences were synthesised and utilised to isolate one clone which contained the genes for the L and M subunits of the reaction centre as well as the α and β subunits of the light‐harvesting complex and part of the gene for the reaction centre cytochrome. The nucleotide sequences of the L and M subunit genes and the derived amino acid sequences are presented. The L subunit consists of 273 amino acids and has a mol. wt of 30 571. The M subunit consists of 323 amino acids and has a mol. wt of 35 902. The primary structure is discussed in the light of the recently published secondary and tertiary structure which has shown that both subunits contain five membrane‐spanning helices.

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Probing the smallest functional unit of the reaction center of Rhodospirillum rubrum G‐9 with proteinases

Cited by 18 publications

References 9 publications

CHEMICALLY MODIFIED PHOTOSYNTHETIC BACTERIAL REACTION CENTERS: CIRCULAR DICHROISM, RAMAN RESONANCE, LOW TEMPERATURE ABSORPTION, FLUORESCENCE AND ODMR SPECTRA AND POLYPEPTIDE COMPOSITION OF BOROHYDRIDE TREATED REACTION CENTERS FROM Rhodobacter sphaeroides R26

CHEMICALLY MODIFIED PHOTOSYNTHETIC BACTERIAL REACTION CENTERS: CIRCULAR DICHROISM, RAMAN RESONANCE, LOW TEMPERATURE ABSORPTION, FLUORESCENCE AND ODMR SPECTRA AND POLYPEPTIDE COMPOSITION OF BOROHYDRIDE TREATED REACTION CENTERS FROM Rhodobacter sphaeroides R26

Transmembrane orientation of α‐helices and the organization of chlorophylls in photosynthetic pigment‐protein complexes

The ‘light’ and ‘medium’ subunits of the photosynthetic reaction centre from Rhodopseudomonas viridis : isolation of the genes, nucleotide and amino acid sequence

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