title: 1H and 15N assignments and secondary structure of the starch-binding domain of glucoamylase from Aspergillus niger.
abstract: 1H and 15N NMR resonance assignments of the granular starch-binding domain (SBD) of glucoamylase from Aspergillus niger have been made by multi-dimensional homonuclear and heteronuclear NMR techniques. Secondary structure analysis based on chemical shifts, 1H-1H NOEs, coupling constants and backbone amide exchange data indicates the presence of a well-defined beta-sheet structure. This consists of one parallel and five antiparallel pairs of beta-strands forming two beta-sheets. Cis-trans isomerisation of proline residues and O-glycosylation of threonine residues are observed and compared between the proteolytically derived SBD fragment and the recombinant protein. Structural features of the SBD in solution were compared to the X-ray crystal structure of a homologous domain of cyclodextrin glycosyltransferase from Bacillus circulans. There are some differences in the locations of the start and end of beta-strands but overall the two structures are very similar. This study will form the basis for the structure determination of the granular SBD and of its complexes.
authors.affiliation: Krebs Institute for Biomolecular Research, Department of Molecular Biology and Biotechnology, University of Sheffield, UK.
authors.forename: A J
authors.initials: AJ
authors.lastname: Jacks
authors.forename: K
authors.initials: K
authors.lastname: Sorimachi
authors.forename: M F
authors.initials: MF
authors.lastname: Le Gal-Coëffet
authors.forename: G
authors.initials: G
authors.lastname: Williamson
authors.forename: D B
authors.initials: DB
authors.lastname: Archer
authors.forename: M P
authors.initials: MP
authors.lastname: Williamson
mesh_terms: D000595:Amino Acid Sequence; D001234:Aspergillus niger / Q000201:enzymology*; D001665:Binding Sites; D005087:Glucan 1,4-alpha-Glucosidase / Q000737:chemistry*; D006031:Glycosylation; D009682:Magnetic Resonance Spectroscopy; D008969:Molecular Sequence Data; D011392:Proline / Q000737:chemistry; D017433:Protein Structure, Secondary; D013213:Starch / Q000378:metabolism*
chemical_list: D013213:Starch; D011392:Proline; D005087:Glucan 1,4-alpha-Glucosidase