Nat. Struct. Biol. 10, 520–526 (2003).

During the proofing stage of this paper, a publication presenting the crystal structure of Kex2, the homolog of furin in yeast, in complex with an inihibitor (Holyoak et al. Biochemistry 42, 6709–6718; 2003) appeared online. We regret not having mentioned this work as a 'Note added in proof'. The full reference for Holyoak et al. is included here.

Holyoak, T. et al. 2.4 Å resolution crystal structure of the prototypical hormone-processing protease Kex2 in complex with an Ala-Lys-Arg boronic acid inhibitor. Biochemistry 42, 6709–6718 (2003).