Sequence conservation in RibD. A total of 550 sequences annotated as both EC 188.8.131.52 and EC 184.108.40.206 in the UniProt database (http://www.uniprot.org/) were filtered at 90% sequence identity and aligned using MUSCLE (Edgar, 2004). Residues that are conserved in at least 70% of the 550 sequences are shown on a black background. The Zn2+-binding residues are marked with a star and assigned secondary-structure elements are shown with the same colour scheme as used in Fig. 2. This figure was prepared using ALINE (Bond & Schüttelkopf, 2009).