Figure 2

Distributions of leucine side chain carbon atoms around the side chains of arginine and lysine in the protein data bank.

(a,b) Position of Leu side chain carbon atoms within 4.5 Å of (a) the NE, CZ, NH1 and NH2 atoms of Arg, or (b) the CD, CE or NZ atoms of Lys in the protein data base shown from the side (top) or front (bottom). In each case the figures show a selection of 4000 atom pairs from the total set of atom pairs identified. Leu carbon atom densities vary from light to dark grey for atoms within 4.5 Å to 3.75 Å, respectively, of the specified side chain atoms. (c) Leu side chain carbon distributions represented according to the coordinate systems (d) below the plots. The y axis is the angle of rotation from the z direction into the x – y plane (i.e. 90° corresponds to Leu side chain carbon atoms in the x – y plane and 180° corresponds to Leu carbon atoms in the -z direction). The x axis corresponds to the rotation around z where 0° defines Leu carbon atoms oriented along x in each coordinate system. Each point corresponds to a Leu side chain carbon atom within 6 Å of the NE, CZ, NH1 or NH2 of arginine (left) or the CD, CE or NZ of Lys (right).