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Research has been conducted on tristetraprolin Nup475, zinc-binding domains. The three-dimensional solution structure of one of the domains has been investigated via the use of multidimensional nuclear magnetic resonance spectroscopy, and the results reveal a fold around the central zinc ion.

The results of NMR studies of a paramagnetic ion Co(II) substituted zinc finger peptide are discussed. These determined the orientation and anisotropy of the magnetic susceptibility tensor. Two methods were used. The first method involved the assignment of resonances for the Co(II) followed by sensor refinement. The second method used an integrated spectrum and yielded a preliminary tensor that provided initial predictions for the Co(II) complex shifts.

A polyanine 26- amino acid peptide characteristic of the TFIIIA-type zinc finger domains has been synthesized and characterized using its metal binding and structural properties. Results show that the peptide folds in the presence of appropriate metal ions to form a complex that has a three-dimensional structure similar to zinc finger domains with more natural sequences. The sequences form a 2:1 peptide/metal complex in which the cysteinate ligands are coordinated to the metal ion but not to histidine.

The structure of a CCHHC Zinc-binding domain from neural zinc finger factor-1 (NZF-1) is obtained in solution though the use of NMR methods. Studies reveal that a two-domain protein fragment interacts with a half-site within a pseudosymmetric DNA binding site and the structure of the domain helps in identifying residues that play significant roles in DNA binding and for designing the future structure.

The use of engineered zinc finger domains and their use for the design of sequence-specific DNA binding proteins are presented. Key examples that reveal the approaches are discussed in detail.

The structure of a CCHHC zinc-binding domain from neural zinc finger factor-I (NZF-1) has been determined in solution though the use of NMR methods. This domain is a member of a family of domains that have the Cys-X[Sub4]-CYS-X[Sub4]-His-X[Sub7]-His-X[Sub5]-Cys consensus sequence. The structure determination reveals a novel fold based around a zinc(II) ion coordinated to three Cys residues and the second of the two conserved His residues. The other His residue is stacked between the metal-coordinated His residue and a relatively conserved aromatic residue. Analysis of His to Gin sequence variants reveals that both His residues are required for the formation of a well-defined structure, but neither is required for high-affinity metal binding at a tetrahedral site. The structure suggests that a two-domain protein fragment and a double-stranded DNA binding site may interact with a common two-fold axis relating the two domains and the two half-sites of the DNA-inverted repeat. [ABSTRACT FROM AUTHOR]

Nup475 (also known as tristetraprolin and TIS11) includes two zinc-binding domains of the form Cys-X[sub 8]-Cys-X[sub 5]-Cys-X[sub 3]-His. These domains are required for rapid degradation of tumor necrosis factor (TNF) and other mRNAs through the interaction with AU-rich elements in their 3'-untranslated regions. The three-dimensional solution structure of the first domain was determined by multidimensional nuclear magnetic resonance spectroscopy, revealing a novel fold around a central zinc ion. The core structure is disklike with a diameter of ∼25 Å and a width of ∼12 Å. This structure provides a basis for evaluating the role of individual residues for structural stability and for nucleic acid binding. [ABSTRACT FROM AUTHOR]