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Figure 5.
Figure 5. Promiscuous Chemokine Binding Facilitated by M3
Conformational Plasticity and Electrostatic Complementation(A)
Comparison of the chemokine binding clefts of M3 alone and the
M3/MCP-1 complex. The top image depicts the open and closed
niches found in the preassociated asymmetric homodimer, viewed
looking edgewise into the binding sites. Chemokine contact
residues highlighted in blue (CTD) and cyan (NTD) and the
corresponding loops that create the binding cleft are labeled.
The middle image is a cartoon depicting the asymmetric
conformation of M3 alone and the symmetric dimer formed in
complex with chemokine. Below is the edgewise view of the M3
chemokine binding cleft with MCP-1 bound, depicted in
magenta.(B) Electrostatic complementarity between M3 and
chemokines. On the right is the surface electrostatic potentials
of the asymmetric M3 dimer (upper image) and the symmetric
M3/MCP-1(P8A) complex (lower image). The view is rotated 90°
relative to the edgewise orientation seen in (A). Negative and
positive electrostatic potentials are mapped to the surfaces in
red and blue for ± 15 KeV using GRASP. In the lower
image, M3 and the chemokines are pulled apart to show their
matched surfaces and charge potentials.
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