|
Figure 3.
Fig. 3. Zinc binding of C1. (a) Detailed view of the zinc
binding site in the structure of C1. Only side chains of Gln208,
His210, Glu223 and His225 are shown. A zinc atom has been
modelled in the binding site. After energy minimisation, the
zinc-ligand distances are 2.27 Å for His210(Ne2), 2.26
Å for His225(Ne2), 1.60 Å for Glu223(Oe1), 1.81
Å for Glu223 (Oe2) and 2.22 Å for Gln208(Oe1). (b)
Plot of chemical shift perturbation against the protein
sequence. The first red line represents the  angle
bracket Δδ  angle
bracket [tot] level, and the second red line is angle
bracket Δδ angle
bracket [tot] + 1*σ. Residues with chemical shift perturbations
above angle
bracket Δδ angle
bracket [tot] + 1*σ are explicitly labelled. (b) Titration
curves for residues in fast exchange for estimating binding
affinity and stoichiometry. (c) Mapping of chemical shift
perturbations on the three-dimensional structure of C1. Residues
with chemical shift perturbations above angle
bracket Δδ angle
bracket [tot] + 1*σ are shown as spheres. The residues expected
to coordinate the zinc are shown in red (histidines) and blue
(glutamate/glutamine), and those with significant perturbations
not expected to be directly involved are shown in green. (d)
Titration curves for residues in fast exchange for estimating
binding affinity and stoichiometry.
|
