Effects of low-molecular-weight polyols on the hydration status of the light-harvesting complex 2 from Rhodobacter sphaeroides 2.4.1

Low-molecular-weight (MW) polyols are organic osmolytes influencing water activity. We have investigated the effects of polyol molecules (glycerol and sorbitol) on the optical and triplet excitation dynamics of light-harvesting complex 2 (LH2) from Rhodobacter (Rba.) sphaeroides in buffer-detergent solutions. The resonance Raman spectroscopy demonstrated that, on increasing glycerol and sorbitol volume fractions ranging from 0 to 80% (v/v) (accompanied by the decreasing water activities), the planar and all-trans conformation of carotenoids (Crts) remained unchanged, and the bacteriochlorophyll a (BChl) Qy absorption intensity decreased. The B850 fluorescence amplitude elevated in the 20–80% v/v sorbitol and 20–40% v/v glycerol solution, but decreased in 80% v/v glycerol solution. The change of 3[Crt*–BChl] interaction bands caused by 3Crt*–BChl interaction had no obvious correlation with water activities against polyol volume fractions, which are rationalized by the water activity sensitive of C- and N-termini of protein which binding with BChls. The results suggest that Rba. sphaeroides LH2 is more sensitive to low-molecular-weight polyols compared with that of the thermophiles purple bacterium Thermochromatium (Tch.) tepidum we had investigated before. Graphic abstract: [Figure not available: see fulltext.]

Yu, JieAffiliated Hospital of Weifang Medical University (författare)
Liu, Yu ChenLund University,Lunds universitet,Kemisk fysik,Enheten för fysikalisk och teoretisk kemi,Kemiska institutionen,Institutioner vid LTH,Lunds Tekniska Högskola,Chemical Physics,Physical and theoretical chemistry,Department of Chemistry,Departments at LTH,Faculty of Engineering, LTH(Swepub:lu)chem-yul (författare)
Wang, PengRenmin University of China (författare)
Zhang, Jian PingRenmin University of China (författare)
Baotou Teachers’ CollegeAffiliated Hospital of Weifang Medical University (creator_code:org_t)

Ingår i:Photochemical and Photobiological Sciences: Springer Science and Business Media LLC20:5, s. 627-6371474-905X1474-9092

Av författaren/redakt...: Shi, Ying; Yu, Jie; Liu, Yu Chen; Wang, Peng; Zhang, Jian Ping

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