TY - JOUR
T1 - Bacterial light-harvesting complexes showing giant second-order nonlinear optical response as revealed by hyper-rayleigh light scattering
AU - Ma, Fei
AU - Yu, Long Jiang
AU - Ma, Xiao Hua
AU - Wang, Peng
AU - Wang-Otomo, Zheng Yu
AU - Zhang, Jian Ping
N1 - Publisher Copyright:
© 2016 American Chemical Society.
PY - 2016/9/8
Y1 - 2016/9/8
N2 - The second-order nonlinear optical (NLO) properties of light-harvesting complexes (LHs) from the purple photosynthetic bacteria Thermochromatium (Tch.) tepidum were investigated for the first time by means of hyper-Rayleigh scattering (HRS). The carotenoid (Car) molecules bound to the isolated LH1 and LH2 proteins gave rise to second-harmonic scattering; however, they showed an opposite effect of the collective contribution from Car, that is, the first hyperpolarizability (β) reduced substantially from (10 510 ± 370) × 10-30 esu for LH1 to (360 ± 120) × 10-30 esu for LH2. Chromatophores of Tch. tepidum also showed a giant hyperpolarizability of (11 640 ± 630) × 10-30 esu. On the basis of the structural information on bacterial LHs, it is found that the effective β of an LH is governed by the microenvironment and orientational correlation among the Car chromophores, which is concluded to be coherently enhanced for LH1. For LH2, however, additional destructive effects between different Car molecules may account for the small β value. This work demonstrates that LH1 and native membranes of purple bacteria can be potent NLO materials and that HRS is a promising spectroscopic means for investigating structural information of pigment-protein supramolecules.
AB - The second-order nonlinear optical (NLO) properties of light-harvesting complexes (LHs) from the purple photosynthetic bacteria Thermochromatium (Tch.) tepidum were investigated for the first time by means of hyper-Rayleigh scattering (HRS). The carotenoid (Car) molecules bound to the isolated LH1 and LH2 proteins gave rise to second-harmonic scattering; however, they showed an opposite effect of the collective contribution from Car, that is, the first hyperpolarizability (β) reduced substantially from (10 510 ± 370) × 10-30 esu for LH1 to (360 ± 120) × 10-30 esu for LH2. Chromatophores of Tch. tepidum also showed a giant hyperpolarizability of (11 640 ± 630) × 10-30 esu. On the basis of the structural information on bacterial LHs, it is found that the effective β of an LH is governed by the microenvironment and orientational correlation among the Car chromophores, which is concluded to be coherently enhanced for LH1. For LH2, however, additional destructive effects between different Car molecules may account for the small β value. This work demonstrates that LH1 and native membranes of purple bacteria can be potent NLO materials and that HRS is a promising spectroscopic means for investigating structural information of pigment-protein supramolecules.
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U2 - 10.1021/acs.jpcb.6b07461
DO - 10.1021/acs.jpcb.6b07461
M3 - Article
C2 - 27505442
AN - SCOPUS:84986550382
VL - 120
SP - 9395
EP - 9401
JO - Journal of Physical Chemistry B
JF - Journal of Physical Chemistry B
SN - 1520-6106
IS - 35
ER -