Low resolution solution structure of the Bacillus subtilis glucose permease IIA domain derived from heteronuclear three-dimensional NMR spectroscopy.

A low resolution solution structure of the IIA domain of the Bacillus subtilis phosphoenolpyruvate-sugar phosphotransferase system (PTS) glucose permease has been determined using 945 inter-residue and 724 intra-residue distance constraints derived from three-dimensional 15N and 13C edited NOESY spectra. A total of 15 structures was generated using distance geometry calculations. The protein is comprised of 13 beta-strands forming an antiparallel beta-barrel. The average backbone atomic RMS deviation about the average distance geometry structure for the beta-sheet residues is 1.1 A. The conformations of the loop regions between the beta-strands are less well determined. Backbone distance constraints obtained during the process of sequential assignment were insufficient to correctly calculate the polypeptide fold.