Resonance Raman Spectroscopy of a Light-Harvesting Protein from the Brown AlgaLaminaria saccharina†

Biochemistry ◽  
1998 ◽  
Vol 37 (8) ◽  
pp. 2450-2457 ◽  
Author(s):  
A. A. Pascal ◽  
L. Caron ◽  
B. Rousseau ◽  
K. Lapouge ◽  
J.-C. Duval ◽  
...  
Keyword(s):  
Raman Spectroscopy ◽  
Light Harvesting ◽  
Resonance Raman Spectroscopy ◽  
Resonance Raman

scholarly journals Blue shifts in bacteriochlorophyll absorbance correlate with changed hydrogen bonding patterns in light-harvesting 2 mutants of Rhodobacter sphaeroides with alterations at α-Tyr-44 and α-Tyr-45

1994 ◽  
Vol 299 (3) ◽  
pp. 695-700 ◽  
Author(s):  
G J S Fowler ◽  
G D Sockalingum ◽  
B Robert ◽  
C N Hunter
Keyword(s):  
Raman Spectroscopy ◽  
Hydrogen Bonds ◽  
Rhodobacter Sphaeroides ◽  
Light Harvesting ◽  
Theoretical Calculations ◽  
Resonance Raman Spectroscopy ◽  
Resonance Raman ◽  
Photosynthetic Bacterium ◽  
Site Directed Mutagenesis ◽  
Aromatic Residues

A combination of Fourier-Transform (FT) resonance Raman spectroscopy and site-directed mutagenesis has been used to examine the function of two highly conserved aromatic residues, alpha-Tyr-44 and alpha-Tyr-45, in the light-harvesting 2 (LH2) complex of the photosynthetic bacterium Rhodobacter sphaeroides. In LH2 complexes, aromatic residues located at positions alpha-44 and alpha-45 are thought to be located near the putative binding site for bacteriochlorophyll, and alterations at these positions are known to produce blue shifts in bacteriochlorophyll absorbance. In the present work, mutant LH2 complexes carrying the alterations alpha-Tyr-44-->Phe, alpha-Tyr-45-->Phe and alpha-Tyr-44,-45-->Phe,Leu were examined. FT resonance Raman spectroscopy of the resulting complexes shows the breakage of a hydrogen bond to the 2-acetyl carbonyl group of one of the B850 bacteriochlorophylls in the LH2 complex; in the double mutant, breakage of a second bond is probable. These results suggest that one of these hydrogen bonds is to alpha-Tyr-44, placing this residue in close proximity to ring I of one of the B850 bacteriochlorophyll a pigments. The breakage of one, then two, 2-acetyl carbonyl hydrogen bonds correlates well with the shift in the absorbance of the B850 pigments of 11 nm then 26 nm at 77 K. Thus a consistency between literature theoretical calculations and the observations from both absorption and FT resonance Raman spectroscopy is demonstrated.

scholarly journals Structure of the retinal chromophore in sensory rhodopsin I from resonance Raman spectroscopy

1989 ◽  
Vol 264 (31) ◽  
pp. 18280-18283
Author(s):  
S P Fodor ◽  
R Gebhard ◽  
J Lugtenburg ◽  
R A Bogomolni ◽  
R A Mathies
Keyword(s):  
Raman Spectroscopy ◽  
Resonance Raman Spectroscopy ◽  
Resonance Raman ◽  
Sensory Rhodopsin ◽  
Retinal Chromophore ◽  
Sensory Rhodopsin I
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