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Figure 1.
Figure 1. Molecular environments of the Glu-P3 (A) and Thr-P2
(B) peptide residues found to be suboptimal for electrostatic
binding in the RT-RH crystal complex. The position of the P3
glutamate (A, atom colors, center) is pointed away from Arg8B
and makes contact with Phe53A. Calculations suggest an
alternative conformation (yellow) that makes better
electrostatic interactions with Arg8B at the expense of packing.
The wild-type P2 threonine residue (B, center) is situated in a
pocket composed of four hydrophobic residues and makes no polar
interactions. The crystal structure of a designed mutant peptide
with a single threonine-to-valine substitution at the P2
position exhibits a structural rearrangement of the Glu-P3
residue (C, atom colors) as compared to the starting sequence
(A). This rearrangement is well supported by calculation (A, C,
yellow).
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