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Title
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The crystal structure of a two zinc-finger peptide reveals an extension to the rules for zinc-finger/DNA recognition.
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Authors
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L.Fairall,
J.W.Schwabe,
L.Chapman,
J.T.Finch,
D.Rhodes.
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Ref.
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Nature, 1993,
366,
483-487.
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PubMed id
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Abstract
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The Cys2-His2 zinc-finger is the most widely occurring DNA-binding motif. The
first structure of a zinc-finger/DNA complex revealed a fairly simple mechanism
for DNA recognition suggesting that the zinc-finger might represent a candidate
template for designing proteins to recognize DNA. Residues at three key
positions in an alpha-helical 'reading head' play a dominant role in
base-recognition and have been targets for mutagenesis experiments aimed at
deriving a recognition code. Here we report the structure of a two zinc-finger
DNA-binding domain from the protein Tramtrack complexed with DNA. The
amino-terminal zinc-finger and its interaction with DNA illustrate several novel
features. These include the use of a serine residue, which is semi-conserved and
located outside the three key positions, to make a base contact. Its role in
base-recognition correlates with a large, local, protein-induced deformation of
the DNA helix at a flexible A-T-A sequence and may give insight into previous
mutagenesis experiments. It is apparent from this structure that zinc-finger/DNA
recognition is more complex than was originally perceived.
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