title: Structural evidence for evolution of the beta/alpha barrel scaffold by gene duplication and fusion.
abstract: The atomic structures of two proteins in the histidine biosynthesis pathway consist of beta/alpha barrels with a twofold repeat pattern. It is likely that these proteins evolved by twofold gene duplication and gene fusion from a common half-barrel ancestor. These ancestral domains are not visible as independent domains in the extant proteins but can be inferred from a combination of sequence and structural analysis. The detection of subdomain structures may be useful in efforts to search genome sequences for functionally and structurally related proteins.
authors.affiliation: European Molecular Biology Laboratory (EMBL) Hamburg Outstation, EMBL c/o Deutsches Elektronen- Synchrotron (DESY), Notkestrasse 85, D-22603 Hamburg, Germany.
authors.forename: D
authors.initials: D
authors.lastname: Lang
authors.forename: R
authors.initials: R
authors.lastname: Thoma
authors.forename: M
authors.initials: M
authors.lastname: Henn-Sax
authors.forename: R
authors.initials: R
authors.lastname: Sterner
authors.forename: M
authors.initials: M
authors.lastname: Wilmanns
mesh_terms: D019747:Aldose-Ketose Isomerases / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism; D020816:Amino Acid Motifs; D000595:Amino Acid Sequence; D000619:Aminohydrolases / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism; D001665:Binding Sites; D002384:Catalysis; D018360:Crystallography, X-Ray; D019143:Evolution, Molecular; D020440:Gene Duplication; D006639:Histidine / Q000096:biosynthesis; D008958:Models, Molecular; D008969:Molecular Sequence Data; D017510:Protein Folding; D017434:Protein Structure, Tertiary; D011995:Recombination, Genetic; D016415:Sequence Alignment; D020124:Thermotoga maritima / Q000201:enzymology
chemical_list: D006639:Histidine; C087227:imidazole glycerol phosphate synthase; D000619:Aminohydrolases; D019747:Aldose-Ketose Isomerases; C079656:Phosphoribosyl-5-amino-1-phosphoribosyl-4-imidazolecarboxiamide isomerase