不同价金属离子介导的蓝膜到紫膜转换的光谱分析

Spectrum Analysis of Blue to Purple Membrane Transition Induced by Diverse Valent Cations

研究了Na+,Mg2+和Tb3+三种不同价金属离子介导的的蓝膜到紫膜转换的可见差光谱,M412产率和M412衰减寿命。结果表明,他们的转换能力有很大差别,三种不同离子介导的吸收变化的中间点的浓度比Na+∶Mg2+∶Tb3+为1∶2.5∶650,同时,在蓝膜到紫膜转换中,其540 nm的吸收变化的曲线与M412产率变化的曲线相符合。当更多的Tb3+加入时,Tb3+介导的重组紫膜的M412衰减寿命有明显延长。而对另两种离子,加入更多时不延长M412衰减寿命。这些结果表明,不同价金属离子与紫膜有不同结合方式。

The visible difference spectra,M412 yield and M412 decay lifetime in blue membrane（bM） to purple membrane（pM） transition induced by Na＋,Mg2＋ and Tb3＋ metal ions were characterized.The transition ability from bM to pM induced by Tb3＋,Mg2＋ and Na＋ has distinguished difference,their concentration ratio at the midpoint of ion-induced absorbance changes is 1∶2.5∶650.Meanwhile,the curve of absorbance changes at 540 nm is similar to that of M412 yield changes in bM to pM transition.The M412 decay lifetime of regenerative pM induced by Tb3＋ was prolonged remarkably when more Tb3＋ was added.However,for the other two ions,additional ions have no effects on its lifetime.These results suggest that diverse valence metal ions exist in different binding ways from pM.