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Figure 4.
Fig. 4. The high point "ridge" in pMHCII ligands is created, in
part, by the peptide. (A) Hydrogen bond network between the CA
peptide and I-A^k. The 10 hydrogen bonds between the CA and
I-A^k are shown as magenta dashed lines. These bonds are
conserved in known pMHCII structures. The helical regions from
I-A^k (colors as in Fig. 3) are shown as a backbone worm diagram
with those side chains and main-chain atoms involved in the
interactions displayed. The H2  1 helix
and H2a and H2b  1 helices
are labeled. (B) Stereo view of the molecular surface of I-A^k (
1 1) together
with the CA peptide (red), showing the surface topology of the
D10 docking platform on the CA/I-A^k ligand. (C) Stereo view of
the molecular surface of H-2Kb ( 1/ 2)
together with the dEV8 peptide (red) (6, 7) in the same view as
in (B), showing the smaller high point on the left side of the
docking platform for the MHC class I-restricted TCR molecule.
The peptide is mostly buried and makes little, if any,
contribution to the elevated points. Those residues contributing
to the high points of the platform are labeled in cyan in (B)
and (C).
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