Author(s)

Zhiping Zhao, Xin Nie, Zongli Hu, Guoping Chen, Zaixin Li, Zhi Zhang

Bioengineering College, Chongqing University, Chongqing, China.
School of Chemistry and Pharmaceutical Engineering, Sichuan University of Science & Engineering, Zigong, China.

Interactions between the light-harvesting subunits and the non-covalently bound photopigments attribute considerably to the spectral properties of photosynthetic bacteria light-harvesting complexes. In our previous studies, we have constructed a novel Rhodobacter sphaeroides expression system. In the present study, we focus on the spectral properties of LH2 when heterologously express LH2 with β-subunit- GFP fusion protein in Rb. sphaeroides. Near infra-red spectrum of LH2 remained nearly unchanged as measured by spectroscopy. Fluorescence spectrum suggested that the LH2 with β-subunit-GFP fusion protein complexes still possessed normal activity in energy transfer. However, photopigments contents were significantly decreased to a very low level in the LH2 with β-subunit-GFP fusion protein complexes compared to that of LH2. FT-IR spectra indicated that interactions between photopigments and LH2 α/β- subunits appeared not to be changed. It was concluded that the LH2 spectral properties exhibited very similar even when heterologously expressed LH2 b-subunit fusion protein in Rb. sphaeroides. Our present study may supply a new insight into better understand the interactions between light-harvesting subunits and photopigments and bacterial photosynthesis and promote the development of the novel Rb. sphaeroides expression system.

LH2; Spectral Property; FT-IR; Photopigment

Zhao, Z. , Nie, X. , Hu, Z. , Chen, G. , Li, Z. and Zhang, Z. (2013) Spectral properties of LH2 exhibit very similar even when heterologously express LH2 with β-subunit fusion protein in Rhodobacter sphaeroides. Advances in Biological Chemistry, 3, 101-107. doi: 10.4236/abc.2013.31013.