Abstract
Glucoamylase from Aspergillus niger is an industrially important biocatalyst that is utilized in the mass production of glucose from raw starch or soluble oligosaccharides. The G1 isoform consists of a catalytic domain and a starch-binding domain connected by a heavily glycosylated linker region. The amino-terminal catalytic domain of the G1 isoform generated by subtilisin cleavage has been crystallized at pH 8.5, which is a significantly higher pH condition than used for previously characterized glucoamylase crystals. The refined structure at 1.9 Å resolution reveals the active site of the enzyme in complex with both Tris and glycerol molecules. The ligands display both unique and analogous interactions with the substrate-binding site when compared with previous structures of homologous enzymes bound to inhibitors.
Publication types
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Comparative Study
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Research Support, Non-U.S. Gov't
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Research Support, U.S. Gov't, Non-P.H.S.
MeSH terms
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Amino Acid Sequence
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Aspergillus niger / enzymology*
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Aspergillus niger / metabolism
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Binding Sites
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Catalytic Domain
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Conserved Sequence
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Crystallization
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Crystallography, X-Ray
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Disulfides / chemistry
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Glucan 1,4-alpha-Glucosidase / chemistry*
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Glucan 1,4-alpha-Glucosidase / metabolism
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Hydrogen Bonding
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Hydrogen-Ion Concentration
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Isoelectric Point
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Isoenzymes / chemistry
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Isoenzymes / metabolism
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Ligands
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Models, Molecular
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Molecular Sequence Data
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Molecular Weight
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Peptides / chemistry
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Peptides / metabolism
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Protein Binding
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Protein Sorting Signals
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Protein Structure, Secondary
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Protein Structure, Tertiary
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Solubility
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Starch / chemistry
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Starch / metabolism
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Substrate Specificity
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Water / chemistry
Substances
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Disulfides
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Isoenzymes
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Ligands
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Peptides
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Protein Sorting Signals
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Water
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Starch
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Glucan 1,4-alpha-Glucosidase