Figure 1.

The minimal scaffold for binding FMN in the NTR superfamily.A, a two-dimensional schematic for one of two polypeptides in the α₂-homodimer indicates regions of α-helix (α), β-strand (β) and the sites for sequence extensions (E1, E2, E3). B, a three-dimensional representation of a native homodimer in which the individual polypeptides are depicted in gray and wheat. This structure is based on a protein (pdb 3E39) within the central hub as described by Akiva et al. (4). FMN is illustrated as a stick drawing with carbon atoms in orange.