The search result changed since you submitted your search request. Documents might be displayed in a different sort order.
  • search hit 1 of 20
Back to Result List

Analysis of absorption spectra of purple bacterial reaction centers in the near infrared region by higher order derivative spectroscopy

  • Reaction centers (RCs) of purple bacteria are uniquely suited objects to study the mechanisms of the photosynthetic conversion of light energy into chemical energy. A recently introduced method of higher order derivative spectroscopy [I.K. Mikhailyuk, H. Lokstein, A.P. Razjivin, A method of spectral subband decomposition by simultaneous fitting the initial spectrum and a set of its derivatives, J. Biochem. Biophys. Methods 63 (2005) 10-23] was used to analyze the NIR absorption spectra of RC preparations from Rhodobacter (R.) sphaeroides strain 2R and Blastochloris (B.) viridis strain KH, containing bacteriochlorophyll (BChl) a and b, respectively. Q(y) bands of individual RC porphyrin components (BChls and bacteriopheophytins, BPheo) were identified. The results indicate that the upper exciton level Py+ of the photo-active BChl dimer in RCs of R. sphaeroides has an absorption maximum of 810nm. The blue shift of a complex integral band at approximately 800nm upon oxidation of the RC is caused primarily by bleaching of Py+, rather thanReaction centers (RCs) of purple bacteria are uniquely suited objects to study the mechanisms of the photosynthetic conversion of light energy into chemical energy. A recently introduced method of higher order derivative spectroscopy [I.K. Mikhailyuk, H. Lokstein, A.P. Razjivin, A method of spectral subband decomposition by simultaneous fitting the initial spectrum and a set of its derivatives, J. Biochem. Biophys. Methods 63 (2005) 10-23] was used to analyze the NIR absorption spectra of RC preparations from Rhodobacter (R.) sphaeroides strain 2R and Blastochloris (B.) viridis strain KH, containing bacteriochlorophyll (BChl) a and b, respectively. Q(y) bands of individual RC porphyrin components (BChls and bacteriopheophytins, BPheo) were identified. The results indicate that the upper exciton level Py+ of the photo-active BChl dimer in RCs of R. sphaeroides has an absorption maximum of 810nm. The blue shift of a complex integral band at approximately 800nm upon oxidation of the RC is caused primarily by bleaching of Py+, rather than by an electrochromic shift of the absorption band(s) of the monomeric BChls. Likewise, the disappearance of a band peaking at 842 nm upon oxidation of RCs from B. viridis indicates that this band has to be assigned to Py+, A blue shift of an absorption band at approximately 830nm upon oxidation of RCs of B. viridis is also essentially caused by the disappearance of Py+, rather than by an electrochromic shift of the absorption bands of monomeric BChls. Absorption maxima of the monomeric BCHls, B-B and B-A are at 802 and 797nm, respectively, in RCs of R. sphaeroides at room temperature. BPheo co-factors H-B and HA peak at 748 and 758 nm, respectively, at room temperature. For B. viridis RCs the spectral positions of HB and HA were found to be 796 and 816nm, respectively, at room temperature.show moreshow less

Export metadata

Additional Services

Search Google Scholar Statistics
Metadaten
Author details:Igor K. Mikhailyuk, Peter P. Knox, Vladimir Z. Paschenko, Andrej P. Razjivin, Heiko Lokstein
URL:http://www.sciencedirect.com/science/journal/03014622
DOI:https://doi.org/10.1016/j.bpc.2006.02.002
Publication type:Article
Language:English
Year of first publication:2006
Publication year:2006
Release date:2017/03/24
Source:Biophysical chemistry. - 122 (2006), 1, S. 16 - 26
Organizational units:Mathematisch-Naturwissenschaftliche Fakultät / Institut für Biochemie und Biologie
Peer review:Referiert
Accept ✔
This website uses technically necessary session cookies. By continuing to use the website, you agree to this. You can find our privacy policy here.