Specific Release of Bacteriochlorophylls B800 of LH2 from Rhodobacter azotoformans Induced by Sodium Dodecyl Sulfate

The release behaviors of bacteriochlorophylls of peripheral light-harvesting complex LH2 from Rhodobacter azotoformans induced by sodium dodecyl sulfate (SDS) were investigated using absorption spectroscopy. The results indicated that bacteriochlorophylls of B800 band are released from their binding sites and transformed into free bacteriochlorophylls by incubating LH2 sample in 10 mmol.L-1 Tris-HCl (pH 8.0) buffer containing SDS of low concentration at room temperature. However, the bacteriochlorophylls of B850 band are not released. The dynamics of B800 release and free BChl formation induced by 0.08% (w/V) SDS can be well fitted by the monoexponential model. The rate constant of B800 release is nearly equal to that of free BChls formation. The release of both B800 and B850 of LH2 can be induced by high concentration SDS, simultaneously. The bacteriochlorophylls of B800 band can be completely transformed into free BChls, but not for B850. Although both of their release processes show monoexponential models in 1% SDS solution, the release rate constant of B850 is remarkably lower than that of B800 and close to that of free BChls formation.国家自然科学基金(No. 30970068)、国家科技基础条件平台建设(No. 2005DKA21209)、厦门大学近海海洋环境科学国家重点实验室高级访问学者基 金(No. MELRS0907)和山西省回国留学人员科研(No. 200713)资助项目