Figure 3.

The CheZ_200-214 peptide-CheY interface. Ribbon representation of (a) the ^F432YZ_200-214 interface and (b) the ^P2(1)2(1)2YZ_200-214 interface. The side chains of key contacting residues are illustrated as ball and stick models and hydrophobic contacts are shown as light green patches. (c) Relative B-factors of CheZ_200-214 in the CheY-CheZ_200-214 structures. The relative B-factor versus CheZ residue number plot in BeF₃₋-free ^F432YZ_200-214 is shown in cyan, that in BeF₃⁻-bound ^F432YZ_200-214 in deep blue and that in BeF₃⁻-bound ^P2(1)2(1)2YZ_200-214 in orange. B_residue is the overall B-factor for each residue and B_CheZ is the overall B-factor for all atoms of CheZ_200-214 included in the final model. (d) Schematic representation of the CheY-CheZ_200-214 contacts. The ^F432Z_200-214 primary sequence in cyan and the ^P2(1)2(1)2Z_200-214 primary sequence in orange are shown on either side of the C-terminal half of CheY, represented in secondary structural elements. Participating residues are highlighted. Hydrophobic contacts are illustrated as solid grey lines, salt bridges as dashed black lines and hydrogen bonds as solid black lines. The BeF₃⁻-free and BeF₃⁻-bound ^F432YZ_200-214 structures solved from crystals grown in Tris (pH 8.4) are used as representatives of ^F432YZ_200-214 structures in this figure.