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PDBsum entry 1cw3
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Oxidoreductase
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PDB id
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1cw3
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Contents |
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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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Human liver mitochondrial aldehyde dehydrogenase: three-Dimensional structure and the restoration of solubility and activity of chimeric forms.
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Authors
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L.Ni,
J.Zhou,
T.D.Hurley,
H.Weiner.
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Ref.
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Protein Sci, 1999,
8,
2784-2790.
[DOI no: ]
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PubMed id
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Abstract
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Human liver cytosolic and mitochondrial isozymes of aldehyde dehydrogenase share
70% sequence identity. However, the first 21 residues are not conserved between
the human isozymes (15% identity). The three-dimensional structures of the beef
mitochondrial and sheep cytosolic forms have virtually identical
three-dimensional structures. Here, we solved the structure of the human
mitochondrial enzyme and found it to be identical to the beef enzyme. The first
21 residues are found on the surface of the enzyme and make no contact with
other subunits in the tetramer. A pair of chimeric enzymes between the human
isozymes was made. Each chimera had the first 21 residues from one isozyme and
the remaining 479 from the other. When the first 21 residues were from the
mitochondrial isozyme, an enzyme with cytosolic-like properties was produced.
The other was expressed but was insoluble. It was possible to restore solubility
and activity to the chimera that had the first 21 cytosolic residues fused to
the mitochondrial ones by making point mutations to residues at the N-terminal
end. When residue 19 was changed from tyrosine to a cysteine, the residue found
in the mitochondrial form, an active enzyme could be made though the Km for NAD+
was 35 times higher than the native mitochondrial isozyme and the specific
activity was reduced by 75%. This residue interacts with residue 203, a
nonconserved, nonactive site residue. A mutation of residue 18, which also
interacts with 203, restored solubility, but not activity. Mutation to residue
15, which interacts with 104, also restored solubility but not activity. It
appears that to have a soluble or active enzyme a favorable interaction must
occur between a residue in a surface loop and a residue elsewhere in the
molecule even though neither make contact with the active site region of the
enzyme.
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Secondary reference #1
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Title
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Structure of mitochondrial aldehyde dehydrogenase: the genetic component of ethanol aversion.
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Authors
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C.G.Steinmetz,
P.Xie,
H.Weiner,
T.D.Hurley.
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Ref.
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Structure, 1997,
5,
701-711.
[DOI no: ]
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PubMed id
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Figure 5.
Figure 5. Interactions between the enzyme and the bound
cofactor from a single subunit in ALDH2. The bound NAD^+
molecule is shown using a ball-and-stick representation and
colored according to atom type. Dashed lines indicate potential
hydrogen-bonding interactions <3.3 Å, except for the interaction
between the peptide nitrogen of Trp168 and the nicotinamide
phosphate which is 3.6 Å (see text). (Figure was produced using
the program MOLSCRIPT [52].)
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The above figure is
reproduced from the cited reference
with permission from Cell Press
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