Figure 2.

Space-filling all-atom presentations affording views of the surface of the NMR structure of OmpX in DHPC micelles (11, 12). (a) Val, Leu, and Ile residues that showed NOEs in a 3D ¹³C-resolved [¹H,¹H]-NOESY spectrum between their methyl protons and the hydrophobic tails of DHPC are colored magenta (groups I and II in Fig. 1a). (b) The residues that showed NOEs between the backbone amide proton and the hydrophobic tails of DHPC in a 3D ¹⁵N-resolved [¹H,¹H]-NOESY spectrum are colored magenta. Residues that had NOEs between the backbone amide proton and the polar head methyls of DHPC, and Trp indole protons with NOEs are colored green and labeled with green lettering. Gray residues in a and b did not show intermolecular NOEs to DHPC. The horizontal broken lines indicate the boundaries between the central hydrophobic surface and the peripheral hydrophilic surface areas of OmpX, and the approximate height of the hydrophobic cylinder jacket is indicated. (c) Distribution of hydrophobic and charged residues on the surface of OmpX in DHPC micelles. Hydrophobic residues are yellow, positively charged and negatively charged residues are blue and red, respectively, and polar residues are gray. The figure has been prepared with the program molmol (36).