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Figure 4.
Figure 4. Topology and ribbon diagrams of the six-bladed
β-propeller domain predicted for the YWTD domain of nidogen. A,
Topology diagram, with each β-sheet given a different color.
Sequence repeats are separated by vertical broken lines. Note
the offset between sequence repeats and β-sheets. Each sheet is
termed a W, with each β-strand representing one leg of the W.
β-Strands are represented by arrows. The disulfide bonds in
nidogen between strands 2 and 3 of W4 and between the 1-2 loop
of W1 and the C-terminal segment in W6 are shown as gold lines.
B, Stereo view ribbon representation, with each β-sheet or
blade of the nidogen β-propeller model given the same color
code as in A. The 4-1 loops that connect each sheet are grey.
The view is up the 6-fold pseudosymmetry axis, with the
“bottom” of the propeller containing the strand 1 to 2
loops, the strand 3 to 4 loops, and the N and C termini of the
propeller domain in the foreground. C, Side view, with the 1-2,
3-4, and N and C termini upward. The side-chain bonds for the
cysteine residues in the two disulfide bonds of the nidogen
β-propeller domain are shown in gold. The β-strands shown as
ribbons are as defined by DSSP [Kabsch and Sander 1983] from the
nido model (see Figure 7 and Table 6). Prepared with MOLMOL
[Koradi et al 1996].
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