title: The crystal structure of Helicobacter pylori HP1029 highlights the functional diversity of the sialic acid-related DUF386 family.
abstract: The proteins of the YhcH/YjgK/YiaL (DUF386) family have been implicated in the bacterial metabolism of host-derived sialic acids and biofilm formation, although their precise biochemical function remains enigmatic. We present here the crystal structure of protein HP1029 from Helicobacter pylori. The protein is a homodimer, in which each monomer comprises a molecular core formed by 12 antiparallel β-strands arranged in two β-sheets flanked by helices. The sandwich formed by the sheets assumes the shape of a funnel opened at one end, with a zinc ion present at the bottom of the funnel. The crystal structure unequivocally shows that HP1029 belongs to the DUF386 family. Although no bioinformatics evidence has been found for sialic acid catabolism in H. pylori, the genomic context of HP1029 in Helicobacter and related organisms suggests a possible role in the metabolism of bacterial surface saccharides, such as pseudaminic acid and its derivatives.
authors.affiliation: Department of Biomedical Sciences, University of Padua, Italy.
authors.forename: Francesca
authors.initials: F
authors.lastname: Vallese
authors.affiliation: Department of Life Sciences, University of Parma, Italy.
authors.forename: Riccardo
authors.initials: R
authors.lastname: Percudani
authors.affiliation: Max von Pettenkofer-Institut für Hygiene und Medizinische Mikrobiologie, Ludwig-Maximilians-Universität, München, Germany.
authors.forename: Wolfgang
authors.initials: W
authors.lastname: Fischer
authors.affiliation: Department of Biomedical Sciences, University of Padua, Italy.
authors.forename: Giuseppe
authors.initials: G
authors.lastname: Zanotti
mesh_terms: D000595:Amino Acid Sequence; D001426:Bacterial Proteins / Q000737:chemistry* / Q000235:genetics; D003001:Cloning, Molecular; D018360:Crystallography, X-Ray; D004926:Escherichia coli / Q000235:genetics / Q000378:metabolism; D015870:Gene Expression; D006193:Haemophilus influenzae; D016480:Helicobacter pylori / Q000737:chemistry* / Q000145:classification / Q000378:metabolism; D008958:Models, Molecular; D008969:Molecular Sequence Data; D010802:Phylogeny; D055503:Protein Multimerization; D017433:Protein Structure, Secondary; D017434:Protein Structure, Tertiary; D011994:Recombinant Proteins / Q000737:chemistry / Q000235:genetics; D016415:Sequence Alignment; D017386:Sequence Homology, Amino Acid; D012794:Sialic Acids / Q000737:chemistry* / Q000378:metabolism; D013400:Sugar Acids / Q000737:chemistry* / Q000378:metabolism
chemical_list: C513444:5,7-diacetamido-3,5,7,9-tetradeoxynonulosonic acid; D001426:Bacterial Proteins; D011994:Recombinant Proteins; D012794:Sialic Acids; D013400:Sugar Acids
keywords: Helicobacter pylori; Pfam family PF04074; YhcH; sialic acid metabolism; zinc binding