ON THE COVER

When two people look very similar, they are said to be doppelgängers. The explanation is that the similar appearances are a coincidence. Cereals and legumes were thought to be the only plant families with Bowman-Birk Inhibitors (BBIs), but these plant families are quite separate. By discovering BBIs in Selaginella and other plant families, James et al. (pages 461–473) show that these protein doppelgängers from cereals and legumes are in fact long-lost cousins. The faces on the cover are stylized lysine residues, the critical residue for inhibiting trypsin, and it was via this lysine and the highly conserved trypsin inhibitory loop around it that the divergent Selaginella BBIs were discovered. (Artwork by Scot Nicholls, Domokun Design.)