title: Structural characterization of the Streptococcus pneumoniae carbohydrate substrate-binding protein SP0092.
abstract: Streptococcus pneumoniae is an opportunistic respiratory pathogen that remains a major cause of morbidity and mortality globally, with infants and the elderly at the highest risk. S. pneumoniae relies entirely on carbohydrates as a source of carbon and dedicates a third of all uptake systems to carbohydrate import. The structure of the carbohydrate-free substrate-binding protein SP0092 at 1.61 Å resolution reveals it to belong to the newly proposed subclass G of substrate-binding proteins, with a ligand-binding pocket that is large enough to accommodate complex oligosaccharides. SP0092 is a dimer in solution and the crystal structure reveals a domain-swapped dimer with the monomer subunits in a closed conformation but in the absence of carbohydrate ligand. This closed conformation may be induced by dimer formation and could be used as a mechanism to regulate carbohydrate uptake.
authors.affiliation: Diamond Light Source, Harwell Science and Innovation Campus, Didcot OX11 0DE, England.
authors.forename: Simone
authors.initials: S
authors.lastname: Culurgioni
authors.affiliation: Diamond Light Source, Harwell Science and Innovation Campus, Didcot OX11 0DE, England.
authors.forename: Minzhe
authors.initials: M
authors.lastname: Tang
authors.affiliation: Diamond Light Source, Harwell Science and Innovation Campus, Didcot OX11 0DE, England.
authors.forename: Martin Austin
authors.initials: MA
authors.lastname: Walsh
mesh_terms: D000595:Amino Acid Sequence; D001426:Bacterial Proteins / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism; D001665:Binding Sites; D003001:Cloning, Molecular; D018360:Crystallography, X-Ray; D004926:Escherichia coli / Q000235:genetics / Q000378:metabolism; D015870:Gene Expression; D008958:Models, Molecular; D009844:Oligosaccharides / Q000737:chemistry* / Q000378:metabolism; D010957:Plasmids / Q000737:chemistry / Q000378:metabolism; D011485:Protein Binding; D000072756:Protein Conformation, alpha-Helical; D000072757:Protein Conformation, beta-Strand; D054730:Protein Interaction Domains and Motifs; D055503:Protein Multimerization; D011956:Receptors, Cell Surface / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism; D011994:Recombinant Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D016415:Sequence Alignment; D017386:Sequence Homology, Amino Acid; D013296:Streptococcus pneumoniae / Q000737:chemistry* / Q000378:metabolism; D013379:Substrate Specificity
chemical_list: D001426:Bacterial Proteins; D009844:Oligosaccharides; D011956:Receptors, Cell Surface; D011994:Recombinant Proteins; C055213:saccharide-binding proteins
keywords: ABC transporters; Streptococcus pneumoniae; carbohydrate uptake; substrate-binding protein SP0092