Near-infrared resonance Raman spectra of Chloroflexus aurantiacus photosynthetic reaction centers

Biochemistry. 1995 Apr 18;34(15):5288-93. doi: 10.1021/bi00015a044.

Abstract

Resonance Raman spectra of the photosynthetic reaction center isolated from the green bacterium Chloroflexus aurantiacus have been obtained with excitation in the near-infrared absorption bands of the special pair (P) and the accessory bacteriochlorophyll (B) using shifted-excitation Raman difference spectroscopy (SERDS). These spectra are compared with the previously reported Raman spectra of P and B in reaction centers from the purple bacterium Rhodobacter sphaeroides. The spectra of P and B from the two species are nearly identical. Common and distinctive attributes of these spectra include enhanced low-frequency (30-200 cm-1) modes in P and the absence of strong Raman activity in modes higher than 1200 cm-1 in both P and B. Also, the absolute scattering cross sections with excitation in the P band are unusually weak in both reaction centers, indicating that their excited states are rapidly vibronically dephased. The striking similarities between the P and B spectra in reaction centers from two very different bacterial species suggest that the common nuclear and electronic dynamics identified here are characteristic of photosynthetic reaction centers.

Publication types

  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, Non-P.H.S.

MeSH terms

  • Bacteria / chemistry*
  • Light-Harvesting Protein Complexes
  • Photosynthetic Reaction Center Complex Proteins / chemistry*
  • Rhodobacter sphaeroides / chemistry
  • Spectrum Analysis, Raman / methods

Substances

  • Light-Harvesting Protein Complexes
  • Photosynthetic Reaction Center Complex Proteins