2.9.1.3	evolution	the putative bipartite ortholog of the bacterial YbbB gene is identified in twelve additional archaeal genomes. Its function is confirmed as a tRNA 2-selenouridine synthase through biochemical and genetic experiments. A phylogenetic analysis of bacterial and archaeal versions of this enzyme provides insights into the early evolution of tRNA 2-selenouridine synthase. The active site loop containing the YbbB-characteristic CXRGGXRS motif near the C-terminus of the rhodanese domain and the Walker A motif (GX4GKT) at the N-terminus of the P-loop domain are highly conserved among the archaeal and bacterial YbbB sequences. The identified archaeal YbbB orthologs represent a bipartite version of bacterial tRNA 2-selenouridine synthase	756718	
2.9.1.3	malfunction	an Escherichia coli mutant deficient in ybbB is incapable of incorporating selenium into tRNA	-, 757134