Identification of Carotenoids in Photosynthetic Proteins: Xanthophylls of the Light Harvesting Antenna - Carotenoids: Physical, Chemical, and Biological Functions and Properties - page 120

1.3

1.2

1.1

1.0

0.9
0.8

Zea

0.7

0.6 Lut

0.5

Vio

0.4

0-1

0-0

0.3

Neo

0.2

0-2

0.1
0.0

380 400 420 440

Wavelength (nm)

460 480 500 520 540

(a)

ν 1

ν 2

ν 3

cis -peaks

Neo

ν 4

Lut

Vio

Zea

1000 1100 1200

Wavenumber (cm -1 )

1500 1525 1550

(b)

FIGURE 7.4 Absorption (a) and resonance Raman (b) spectra of the four major xanthophylls of LHCII
antenna: zeaxanthin (Zea), lutein (Lut), violaxanthin (Vio), and neoxanthin (Neo).

Resonance Raman spectra of all four LHCII xanthophylls reveal differences in the n 1 frequen-
cies, which normally depends upon the conjugation number (Heyde et al., 1971; Rimai et al., 1973).
In addition, the neoxanthin transition is further upshifted rel ecting the cis -conformation. The n 1
region of this xanthophyll possesses additional bands at 1120, 1132, and 1203 cm −1 characteristic for
the 9- cis coni guration (Hu et al., 1997). The n 3 band frequency also differs in these xanthophylls.
Finally, n 4 is small and featureless in all isolated pigments.