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Figure 3.
Crystal structures of the six-helix bundles formed by NHR
α-peptide 1 in complex with α-peptide 3, α/β-peptide 10, or
chimeric α/β-peptide 8. (A) Views from the side and looking
down the superhelical axis of the indicated six-helix bundles.
NHR helices are colored gray, CHR helices are colored by residue
type (yellow for α, cyan for β^3, and red for cyclic β). (B)
Overlay of the all α-peptide helix bundle formed 1+3 with that
formed by 1+10 or 1+8. The CHR helix from 1+3 is colored green;
otherwise, coloring is the same as in A. In A and B, the
structures viewed from the side are oriented with the CHR N
terminus at the top of the page; the structures viewed down the
superhelical axis are oriented with the CHR N terminus
projecting out of the page. (C) Packing interactions of CHR
residues Trp[3], Trp[6], and Ile[10] (shown as sticks) against
the NHR core trimer (shown as surface) in the structures of 1+3,
1+10, and 1+8; in the structure of 1+10, neither Trp[3] nor
Trp[6] was resolved in electron density past C[β], and a
molecule of glycerol (shown as sticks) was observed in the
Trp[6] binding cavity. Coloring is the same as in A.
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