Multiple sequence alignment of the eukaryotic translation initiation eIF-5A protein family with their archaeal homologs and the bacterial translation elongation EF-P family. The minimum domain of eukaryotic IF-5A needed for hypusine modification (51) is boxed; the asterisk denotes the lysine residue that is posttranslationally modified to hypusine. Protein names (and accession number—when different) are as follows: IF5A_METJA, M. jannaschii aIF-5A; IF5A-METTH, M. thermoautotrophicum unpublished ORF; IF5A-ARCFU, A. fulgidus unpublished ORF; IF5A_SULAC, Sulfolobus acidocaldarius aIF-5A; IF5A_HUMAN, human eIF-5A; IF5A_DICDI, Dictyostelium discoideum eIF-5A; IF51_YEAST, S. cerevisiae eIF-5A; IF52_CAEEL, Caenorhabditis elegans eIF-5A; EFP_BACSU, B. subtilis EF-P; EFP_SYNY3, Synechocystis sp. EF-P; EFP_ECOLI, E. coli EF-P; EFP_HELPY, Helicobacter pylori EF-P.