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Title
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Two-dimensional NMR study of a protein-DNA complex. lac repressor headpiece-operator interaction.
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Authors
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R.Kaptein,
R.M.Lamerichs,
R.Boelens,
J.A.Rullmann.
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Ref.
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Biochem Pharmacol, 1990,
40,
89-96.
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PubMed id
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Abstract
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The interaction of the N-terminal DNA-binding domain (56 amino acid residues) of
the lac repressor with lac operator DNA was analyzed using two-dimensional NMR
spectroscopy. Both half-operators (11 and 14 bp) and a complete fully symmetric
22 bp operator were studied. Two-dimensional nuclear Overhauser effect (2D NOE)
spectra of headpiece-operator complexes were taken in both D2O and H2O
solutions. Special attention was given to the problem of 1H resonance
assignments. Based on an analysis of the proton-proton NOEs, a model for the
headpiece-operator complex could be derived. In this model, most of the
protein-DNA contracts occur between amino acid residues in the second helix
(recognition helix) of the lac headpiece and DNA bases in the major groove. The
orientation of this helix with respect to the dyad axis of the operator is
opposite to that found in the X-ray structures of several other
repressor-operator complexes.
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