Figure 2.

Sulfation at CXCR4 sites Y7 and Y12 results in hydrogen bonding across the dimer interface. CXCR4 N-terminal chains shown in blue and green; SDF-1 molecules shown in yellow and pink. Representative hydrogen bonds in simulation snapshots are shown for sulfation sites on one CXCR4 N-terminus as follows: (a) between Y21, and SDF-1 residue R47 on the same side of the dimer interface, (b) between Y7, and SDF-1 residue R20 on the opposite side of the dimer interface, and (c) between Y12, and SDF-1 residue K24 on the opposite side of the dimer interface. [Color figure can be viewed in the online issue, which is available at http://wileyonlinelibrary.com.]