The Crystal Structure of Decameric BslA Reveals Two Distinct Structural
Forms. From the data presented thus far, we suggest that the cap
region of monomeric BslA is a random coil in aqueous solution
with the hydrophobic side chains buried; at an interface the cap
restructures to form a β-sheet, and self-assembles into a 2D lattice.
Further supporting data for this model comes from the X-ray
crystal structure (10): analysis reveals two substantially different
cap configurations in the decameric repeat unit (Fig. 4A). Eight of
the ten subunits are positioned with their caps in close proximity in
a micelle-like arrangement. In these proteins, the cap regions are
n a β-sheet configuration with the hydrophobic residues oriented