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Figure 5.
Surface representations of C4BP12. The closest to mean
structure of residues 1-124 is shown. A, surface representation,
indicating residues that show chemical shift changes upon M4-N
binding. Blue, small combined chemical shift difference (see
below); red, large chemical shift difference, unable to track
cross-peak. Residues for which no ^NH shift information could be
obtained (either proline residues or due to overlap in the HSQC
spectra) are colored gray. B, electrostatic surface potential,
Calculated using the Adaptive Poisson-Boltzmann Solver (49)
plug-in within PyMOL: red is negative charge, and blue is
positive charge. A range of -5/+5 kT was used. Those amino acids
substituted in a mutagenesis study are marked. C, same view of
the surface (transparent with backbone trace underneath) with
residues that show chemical shift changes upon M4-N binding
colored according to position: yellow, close to the interface
(the chemical shift of these could be influenced by intermodular
reorientation or direct contact); cyan, residues away from the
interface likely to be in direct contact with M4-N. The aromatic
side chains of Tyr^37, Tyr^62, and Phe^84 are shown in
space-fill representation. D, sequence of C4BP12 illustrating
the ^NH chemical shift changes on addition of M4-N. The residues
are colored as follows: black, no apparent change (combined
chemical shift difference √((Δδ^NH)^2 + (Δδ^15N/5)^2 <
0.08 ppm); gray, data missing; blue, small shift (combined
chemical shift difference of >0.08 ppm, <0.2 ppm but able to
trace peak movement); red, large shift (unable to track peak).
All figures produced using PyMOL (http://www.pymol.org).
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