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PDBsum entry 1azh
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References listed in PDB file
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Key reference
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Title
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Three-Dimensional structures of three engineered cellulose-Binding domains of cellobiohydrolase i from trichoderma reesei.
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Authors
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M.L.Mattinen,
M.Kontteli,
J.Kerovuo,
M.Linder,
A.Annila,
G.Lindeberg,
T.Reinikainen,
T.Drakenberg.
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Ref.
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Protein Sci, 1997,
6,
294-303.
[DOI no: ]
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PubMed id
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Abstract
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Three-dimensional solution structures for three engineered, synthetic CBDs (Y5A,
Y31A, and Y32A) of cellobiohydrolase I (CBHI) from Trichoderma reesei were
studied with nuclear magnetic resonance (NMR) and circular dichroism (CD)
spectroscopy. According to CD measurements the antiparallel beta-sheet structure
of the CBD fold was preserved in all engineered peptides. The three-dimensional
NMR-based structures of Y31A and Y32A revealed only small local changes due to
mutations in the flat face of CBD, which is expected to bind to crystalline
cellulose. Therefore, the structural roles of Y31 and Y32 are minor, but their
functional importance is obvious because these mutants do not bind strongly to
cellulose. In the case of Y5A, the disruption of the structural framework at the
N-terminus and the complete loss of binding affinity implies that Y5 has both
structural and functional significance. The number of aromatic residues and
their precise spatial arrangement in the flat face of the type I CBD fold
appears to be critical for specific binding. A model for the CBD binding in
which the three aligned aromatic rings stack onto every other glucose ring of
the cellulose polymer is discussed.
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