Relationships between physical features of β-sheet components and the definition of the computational search spaces.

(A) variable definitions as used in Materials and Methods. The two vertical beta-strands form a single strand-pair, with odd residues labeled in white and even residues in black. The strands share the same orientation o and extend from p to p+l and from q to q+l. (B) structure of the lattice of the β-strand search space defined by the variables p (location), l (length), and o (orientation). Changes in the parameters of a β-strand are physically possible in a single step only along the paths marked by arrows. The arrowheads therefore define the relative locations queried by the maxima-finding algorithm at each point. (C) structure of the lattice of the strand-pair search space defined by the variables p (first strand location), q (second strand location), l (length) and o (orientation, not shown). In addition to the physically possible changes in B, shifts of one or two residues in the relative strand positions are possible. Arrowheads indicate the relative locations queried by the strand-pair maxima-finding algorithm for each point.