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

Beese, D.; Steiner, Robert F.; Scheer, Hugo; Angerhofer, Alexander; Robert, Bruno; Lutz, Marc

doi:10.1111/j.1751-1097.1988.tb02729.x

Cited by 34 publications

(23 citation statements)

References 39 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…It was generally accepted (but see [22]), that treatment with borohydride removed about 50% of the monomeric bacteriochlorophylls absorbing at 802 nm. From kinetic and spectroscopic evidence it had been suggested that the 'inactive' BChl q (BB) , is reduced at the 3-acetyl group by this treatment, and then subsequently lost from the remaining complex [9,21,[23][24][25]. As a side reaction, partial cleavage of the M-subunit has been observed in the case of Rb.…”

Section: Introductionmentioning

confidence: 99%

Modified bacterial reaction centers. 4. The borohydride treatment reinvestigated: comparison with selective exchange experiments at binding sites BA,B and HA,B

Struck¹,

Müller²,

Scheer³

1991

Biochimica et Biophysica Acta (BBA) - Bioenergetics

Self Cite

View full text Add to dashboard Cite

Pigments of borohydride-treated reaction centers of Rhodobacter sphaeroides R 26 and Rhodopseudomonas viridiswere analyzed by HPLC with polychromatie detection. In both species, pigment composition and contents were unchanged. Reaction centers from Rhodobacter sphaeroides R26 were prepared in which bacteriochlorophylls (B A B) and bacteriopheophytins (HA, n) were exchanged with their potential borohydride products reduced at C-3 t.[3-Hydroxyethyl]-BChl a exchanges selectively into the BA, B pockets, and 31-OH-BPh a to the HA, B pockets. Stable reaction centers are obtained in both cases. A comparison of the absorption and circular dichroism spectra of reaction centers after exchange with 31-OH pigments, and of borohydride-modified reaction centers, reveal distinct differences. It is concluded that during borohydride reduction none of the pigments is chemically modified or extracted from the reaction centers.

show abstract

Section: Introductionmentioning

confidence: 99%

Modified bacterial reaction centers. 4. The borohydride treatment reinvestigated: comparison with selective exchange experiments at binding sites BA,B and HA,B

Struck¹,

Müller²,

Scheer³

1991

Biochimica et Biophysica Acta (BBA) - Bioenergetics

Self Cite

View full text Add to dashboard Cite

show abstract

“…

Incubation of photosynthetic reaction centers from Rhodobucter sphaeroides R26 with exogenous lY-OH-bacteriochlorophyll ar or aoo according to Scheer et al (1987) results in the exchange of endogenous bacteriochlorophyll ar. The exchange amounts to 5 50% according to HPLC analysis, corresponding to a complete replacement of the 'monomeric' bacteriochlorophylls, Bu and Br, by exogenous pigment.

…”

mentioning

confidence: 99%

Modified reaction centers from Rhodobacter sphaeroides R26

Struck¹,

Scheer²

1990

FEBS Letters

Self Cite

View full text Add to dashboard Cite

Incubation of photosynthetic reaction centers from Rhodobucter sphaeroides R26 with exogenous lY-OH-bacteriochlorophyll ar or aoo according to Scheer et al. (1987) results in the exchange of endogenous bacteriochlorophyll ar. The exchange amounts to 5 50% according to HPLC analysis, corresponding to a complete replacement of the 'monomeric' bacteriochlorophylls, Bu and Br, by exogenous pigment. The absorption spectra show small, but distinct changes in the Qx-region of the bacteriochlorophylls, and bleaching of the modified reaction centers is retained. The corresponding binding sites must be accessible from the exterior, and allow for the introduction of a polar residue at C-1P. This is supported by the observation of side reactions of the endogenous 'monomeric' bacteriochlorophylls within the reaction center pigments, e.g. epimerization and hydroxylation at C-l32.

show abstract

“…However, this Interpretation has been challenged by the finding of (1) an unchanged pigment composition in BH4 -treated RCs (Struck et al, 1992a), (2) a tetrapyrrolic pigment at the B" site in the poorly resolved X-ray structure (J. Allen, personal communication, 1991), and (3) at least partial proteolysis of the M subunit (Beese et al, 1987). The BH4~ reduction also leads to distinet changes in Chlorophyll proteins of higher plants, but these changes have not yet been investigated at a molecular level ).…”

Section: "Double Mutant H-l153-s/h-m180-s Binds Two Bchl a At Ba1imentioning

confidence: 99%

“…This Option was indicated by the finding of Walter et al (1979) that different esterüying alcohols are present in Bphea and Bchla of Rs. rubrum RCs, in conjunetion with the finding that these RCs did not discriminate strongly between pigments bearing phytol or geranylgeraniol (Scheer et al, 1987;Beese, 1989;Struck, 1991). The mutagenesis experiments (Table 0 suggest the same mechanism if the exchange of the amino acid next to the central N-4 cavity at any one of the positions is not assumed to bestow these sites indiscriminately with dechelafase activities.…”

mentioning

confidence: 97%

“…Therefore, the researchers concluded that one of these pigments (most likely BB) was attacked selectively by the reagent and subsequently lost from the RC (Ditson etal, 1984; Maroti etal, 1985; Beese etal, 1987; Chadwick etal, 1987;Frank, 1990;Frank and Violette, 1989). However, this Interpretation has been challenged by the finding of (1) an unchanged pigment composition in BH4 -treated RCs (Struck et al, 1992a), (2) a tetrapyrrolic pigment at the B" site in the poorly resolved X-ray structure (J. Allen, personal communication, 1991), and (3) at least partial proteolysis of the M subunit (Beese et al, 1987). The BH4~ reduction also leads to distinet changes in Chlorophyll proteins of higher plants, but these changes have not yet been investigated at a molecular level ).…”

mentioning

confidence: 98%

See 1 more Smart Citation

Bacterial Reaction Centers with Modified Tetrapyrrole Chromophores

Scheer¹,

Hartwich²

Advances in Photosynthesis and Respiration

View full text Add to dashboard Cite

II. Norris, James R., Date. QP517.P45P46 1993 '3342-dc20 92-43633This book is printed on acid-free paper.© Academic Press, Inc. References 78 Genetic Analysis of Photosynthetic Membrane Biogenesis in Rhodobacter sphaeroides I. IntroductionSeveral different methods are available for preparing reaction centers with nonnative chromophores: (1) (re)assembly from the Polypeptides, pigments, and other components such as quinones, iron, and possibly others; (2) exchange of chromophores into native or partly denatured reaction centers; (3) modification of chromophores in native or partly denatured reaction centers by chemical or enzymatic means; (4) modification of binding sites to incorporate different chromophores, for example, by mutagenesis, and (5) mutagenic modifications of the pigments biosynthetic pathways. With the exception of the last one, all these approaches have been used on different Complete reconstitution of the complexes (Method 1) from the isolated constituent Polypeptides and suitably modified pigments is likely to have the greatest potential, but to date has been impossible with reaction centers. This technique has been applied successfully to the core light-harvesting complexes (LHCI) of purple bacteria (Miller et al, 1987;Ghosh et al, 1988;Parkes-Loach et al, 1988 Chang et al, 1990a,b;Heller and Loach, 1990) and to the peripheral light-harvesting chromoprotein LHCII-ß of higher plants (Plumley and Schmidt, 1987). The method has been extended by Paulsen etat. (1990Paulsen etat. ( ,1991 to the full-length and modified LHCII-ß precursor Polypeptides expressed in and isolated from Escherichia coli and by Schmidt et al. (1991) to other green plant peripheral light-harvesting complexes.Site-directed mutagenesis of the binding pockets (Method 4) has been used extensively to exchange bacteriochlorophylls (Behls) with their metalfree derivatives, for example, bacteriopheophytins (Bphes) and vice versa in reaction centers (RCs) from Rhodobacter (Rb.) capsulatus and Rb. sphaeroides (Table I)-With only a Single exception, whenever the histidine(s) ligating the central magnesium atom(s) of the Bchl(s) were replaced by hydrophobic amino acids, stably assembled RCs were obtained in which the Behls at the respective site(s) were replaced by Bphe to yield stably assembled and isolatable RCs (Bylina and Youvan, 1988; Coleman and Youvan, 1990;Robles et al, 1990;Schenck et al, 1990;Woodbury et al, 1990). In reversing this reaction, replacement of leucine or isoleucine next to the central N-4 cavity of Bphe with histidine resulted in binding of Behl at the respective site. Some results are available with amino acid residues of intermediate ligation strength. Serine or threonine selected binding of Behl at BA and BB (Bylina et al, 1990); glutamine (mutants H-L173Q and H-M200Q 2 ) at the sites of the special pair resulted in binding of Behl also (Bylina and Youvan, 1988). Omission of Bphe HL was found in a mutant of Rb. capsulatus in which part of the D helix of subunit L was replaced by the symmetrically equiv...

show abstract

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

Cited by 34 publications

References 39 publications

Modified bacterial reaction centers. 4. The borohydride treatment reinvestigated: comparison with selective exchange experiments at binding sites BA,B and HA,B

Modified bacterial reaction centers. 4. The borohydride treatment reinvestigated: comparison with selective exchange experiments at binding sites BA,B and HA,B

Modified reaction centers from Rhodobacter sphaeroides R26

Bacterial Reaction Centers with Modified Tetrapyrrole Chromophores

Contact Info

Product

Resources

About