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PDBsum entry 1sp2
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References listed in PDB file
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Key reference
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Title
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Structures of zinc finger domains from transcription factor sp1. Insights into sequence-Specific protein-Dna recognition.
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Authors
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V.A.Narayan,
R.W.Kriwacki,
J.P.Caradonna.
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Ref.
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J Biol Chem, 1997,
272,
7801-7809.
[DOI no: ]
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PubMed id
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Abstract
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The carboxyl terminus of transcription factor Sp1 contains three contiguous
Cys2-His2 zinc finger domains with the consensus sequence
Cys-X2-4-Cys-X12-His-X3-His. We have used standard homonuclear two-dimensional
NMR techniques to solve the solution structures of synthetic peptides
corresponding to the last two zinc finger domains (Sp1f2 and Sp1f3,
respectively) of Sp1. Our studies indicate a classical Cys2-His2 type fold for
both the domains differing from each other primarily in the conformation of
Cys-X2-Cys (beta-type I turn) and Cys-X4-Cys (beta-type II turn) elements. There
are, however, no significant differences in the metal binding properties between
the Cys-X4-Cys (Sp1f2) and Cys-X2-Cys (Sp1f3) subclasses of zinc fingers. The
free solution structures of Sp1f2 and Sp1f3 are very similar to those of the
analogous fingers of Zif268 bound to DNA. There is NMR spectral evidence
suggesting that the Arg-Asp buttressing interaction observed in the Zif-268.DNA
complex is also preserved in unbound Sp1f2 and Sp1f3. Modeling Sp1-DNA complex
by overlaying the Sp1f2 and Sp1f3 structures on Zif268 fingers 1 and 2,
respectively, predicts the role of key amino acid residues, the
interference/protection data, and supports the model of Sp1-DNA interaction
proposed earlier.
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Figure 8.
Fig. 8. Summary of proposed DNA contacts between Sp1f2 and
Sp1f3 with their respective 3-base pair subsites. The proposed
amino acid-DNA base contacts are shown by a solid line. The
other probable^ amino acid-DNA base interactions within the
framework are indicated^ by dotted lines. Note the antiparallel
orientation of peptide^ and DNA and absence of any direct
contacts with the other C-rich strand of DNA duplex (not shown).
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Figure 9.
Fig. 9. A, stereo presentation of the superposition of
Sp1f2·avg·min (see "Experimental Procedures") and
Zif268 finger 1. Residues 3-27 (excluding the loop between the
two Cys residues) of Sp1f2·min·avg (dark) were
superimposed on the corresponding residues of Zif268^ finger 1
(light). B, stereo presentation of the superposition of
Sp1f3·avg·min (see "Experimental Procedures") and
Zif268 finger 2. Residues 3-25 (excluding Pro9) of
Sp1f3·min·avg (dark) were superimposed on the
corresponding residues of Zif268 finger 2 (light).
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The above figures are
reprinted
by permission from the ASBMB:
J Biol Chem
(1997,
272,
7801-7809)
copyright 1997.
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