Preliminary structural characterisation of the 33 kDa protein (PsbO) in solution studied by site-directed mutagenesis and NMR spectroscopy

Abstract

Site-directed mutagenesis experiments combined with 1D and 2D NMR spectra provide a preliminary insight into the structure and dynamics of the 33 kDa protein (PsbO) from T. elongatus free in solution. The NMR spectra suggest that PsbO rather than forming a ‘molten globule’ state or being ‘natively unfolded’, contains both a well folded core and highly flexible regions. This core shows remarkable stability over a broad range of temperatures and pH values. Additional experiments with Cys residues introduced at different positions indicate sites of increased accessibility/flexibility which may be important for the docking to the PS2 core complex.