Figure 4
Tetrameric organization of PepTSo2. (a, b, c) The overall structure of tetrameric PepTSo2 is viewed from the (a) extracellular, (b) membrane and (c) intracellular sides. The four protomers are colored magenta, green, blue and yellow. The rectangles labeled `d' and `e' indicate the regions highlighted in (d) and (e), respectively. (d, e) The intermolecular interactions of the extracellular loop (ECL) with H12 of the neighboring protomer are viewed from the (d) extracellular and (e) membrane sides. The possible hydrogen bonds of up to 3.2 Å are shown as black dotted lines. (f) A 2mFo − DFc electron-density map of the interacting area between the ECL and H12 contoured at 1.1σ. The C atoms of the two protomers are colored magenta and green. (g) Sequence alignment of PepTSo2 with other prokaryotic POT families in the ECL area. (h) FSEC-based mutational analyses of PepTSo2. The peak corresponding to tetrameric PepTSo2 is marked with an asterisk. |