title: Fold-recognition analysis predicts that the Tag protein family shares a common domain with the helix-hairpin-helix DNA glycosylases.
abstract: The Escherichia coli protein Tag is traditionally regarded as an archetype of one of four classes of N-alkylpurine DNA glycosylases. However, its structure and phylogenetic relationship to other glycosylases remains a mystery. Fold-recognition and sequence profile analyses suggest that Tag shares the catalytic domain with helix-hairpin-helix (HhH) glycosylases such as MutY, AlkA and EndoIII, but its N- and C-termini together form a unique His2Cys2 cluster. The findings presented in this paper provide insight into sequence-structure-function relationships in the Tag family and should aid in a more precise definition of the common core of the HhH superfamily of glycosylases involved in DNA repair.
authors.affiliation: Bioinformatics Laboratory, International Institute of Molecular and Cell Biology, ul. ks. Trojdena 4, 02-109, Warsaw, Poland. iamb@wp.pl
authors.forename: Janusz M
authors.initials: JM
authors.lastname: Bujnicki
authors.forename: Leszek
authors.initials: L
authors.lastname: Rychlewski
mesh_terms: D000595:Amino Acid Sequence; D000941:Antigens; D019295:Computational Biology; D045647:DNA Glycosylases; D004260:DNA Repair; D043224:Deoxyribonuclease (Pyrimidine Dimer); D004706:Endodeoxyribonucleases / Q000737:chemistry*; D029968:Escherichia coli Proteins; D019077:Helix-Turn-Helix Motifs; D006801:Humans; D019476:Insect Proteins / Q000737:chemistry; D008969:Molecular Sequence Data; D009699:N-Glycosyl Hydrolases / Q000737:chemistry*; D011487:Protein Conformation; D017510:Protein Folding; D017434:Protein Structure, Tertiary; D017386:Sequence Homology, Amino Acid
chemical_list: D000941:Antigens; D029968:Escherichia coli Proteins; D019476:Insect Proteins; C428611:TAg5 protein, Glossina morsitans morsitans; D004706:Endodeoxyribonucleases; D043224:Deoxyribonuclease (Pyrimidine Dimer); C106403:NTH protein, E coli; D045647:DNA Glycosylases; D009699:N-Glycosyl Hydrolases; C061738:mutY adenine glycosylase; C076131:DNA-3-methyladenine glycosidase II