Mg2+-induced LHC II aggregation in thylakoid membrane

Mg2+-induced changes in 77K fluorescence spectra of wheat thylakoid membran es were analyzed by a Gaussian deconvolution program. All spectra were fitt ed well with 7 Gaussian sub-bands. The sub-band areas for the LHC II macroa ggregate (F-699) and PS II (F-685 and F-695) were increased and those for t he LHC II trimer (F-681) and PS I (F-729 and F-740) were decreased by Mg2+. Moreover, it was Found that the sub-band area ratio for F-699 over F-681 w as dramatically enhanced by Mg2+ by 1.72 times. It was concluded that the L HC II trimer in thylakoid membranes could be aggregated and transformed int o its macroaggregate by Mg2+ on a large scale. The possible implication of the Mg2+-induced LHC II aggregation was also discussed.