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PDBsum entry 1mg2
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Oxidoreductase
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PDB id
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1mg2
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Contents |
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382 a.a.
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125 a.a.
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105 a.a.
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147 a.a.
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* Residue conservation analysis
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References listed in PDB file
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Key reference
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Title
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Mutation of alphaphe55 of methylamine dehydrogenase alters the reorganization energy and electronic coupling for its electron transfer reaction with amicyanin.
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Authors
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D.Sun,
Z.W.Chen,
F.S.Mathews,
V.L.Davidson.
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Ref.
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Biochemistry, 2002,
41,
13926-13933.
[DOI no: ]
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PubMed id
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Abstract
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Methylamine dehydrogenase (MADH) possesses an alpha(2)beta(2) structure with
each smaller beta subunit possessing a tryptophan tryptophylquinone (TTQ)
prosthetic group. Phe55 of the alpha subunit is located where the substrate
channel from the enzyme surface opens into the active site. Site-directed
mutagenesis of alphaPhe55 has revealed roles for this residue in determining
substrate specificity and binding monovalent cations at the active site. It is
now shown that the alphaF55A mutation also increases the rate of the true
electron transfer (ET) reaction from O-quinol MADH to amicyanin. The
reorganization energy associated with the ET reaction is decreased from 2.3 to
1.8 eV. The electronic coupling associated with the ET reaction is decreased
from 12 to 3 cm(-1). The crystal structure of alphaF55A MADH in complex with its
electron acceptors, amicyanin and cytochrome c-551i, has been determined. Little
difference in the overall structure is seen, relative to the native complex;
however, there are significant changes in the solvent content of the active site
and substrate channel. The crystal structure of alphaF55A MADH has also been
determined with phenylhydrazine covalently bound to TTQ in the active site.
Phenylhydrazine binding significantly perturbs the orientation of the TTQ rings
relative to each other. The ET results are discussed in the context of the new
and old crystal structures of the native and mutant enzymes.
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Secondary reference #1
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Title
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Structure of an electron transfer complex: methylamine dehydrogenase, Amicyanin, And cytochrome c551i.
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Authors
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L.Chen,
R.C.Durley,
F.S.Mathews,
V.L.Davidson.
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Ref.
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Science, 1994,
264,
86-90.
[DOI no: ]
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PubMed id
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