Fig. 4.

Alignments of the RSH 28-aa repetitive motif. (A) Head-to-head parallel alignment gives di-Idt motifs exclusively. (B) Staggered alignment gives pulcherosine motifs exclusively. This shows facile generation of pulcherosine cross-linking motifs. Offsetting the 28-residue canonical RSH motif by 12 residues realigns the Ser-Hyp₄ glycomodule of one chain with another (underlined), thus switching from potential di-Idt to pulcherosine cross-links. Hydrophilic residues are shown in yellow, potential di-Idt and pulcherosine cross-links (hydrophobic) are in pink, and other hydrophobic residues are in gray. All motifs are presented in the N terminus (head) to C terminus (tail) direction.