1chc
From Proteopedia
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STRUCTURE OF THE C3HC4 DOMAIN BY 1H-NUCLEAR MAGNETIC RESONANCE SPECTROSCOPY; A NEW STRUCTURAL CLASS OF ZINC-FINGER
Overview
A recently identified sequence motif, referred to as "C3HC4" (also "RING, finger" and "A Box") for its distinctive pattern of putative metal-binding, residues, has been found in a wide range of proteins. In a previous paper, we described the expression and purification of fragments encompassing, this motif from the Vmw110 (IPC0) protein family. We showed that the, equine herpes virus protein binds zinc ions and adopts a beta beta alpha, beta fold. We now report the tertiary structure of this domain in, solution, as determined by two-dimensional 1H-NMR An amphipathic, alpha-helix lies along one surface of a triple-stranded beta-sheet. Four, pairs of metal-binding residues sequester two zincs at distinct, tetrahedral sites. The first and third pairs bind one metal ion, while the, second and fourth pairs bind the other, forming an interleaved whole. The, first and the fourth pairs are contained within two prominent, well-defined loops related by an approximate dyad symmetry. Conserved, residues within the helix, sheet and loops contribute to a compact, hydrophobic core. The region comprising the first two beta-strands and the, alpha-helix has remarkable structural similarity with a TFIIIA type of, zinc finger, even though the C3HC4 domain appears not to bind specifically, to DNA or RNA. Using site-directed mutagenesis we demonstrate that exposed, polar side-chains of the C3HC4 alpha-helix are essential for, trans-activation of gene expression by an intact herpes virus regulatory, protein.
About this Structure
1CHC is a Single protein structure of sequence from Equid herpesvirus 3 with ZN as ligand. Full crystallographic information is available from OCA.
Reference
Structure of the C3HC4 domain by 1H-nuclear magnetic resonance spectroscopy. A new structural class of zinc-finger., Barlow PN, Luisi B, Milner A, Elliott M, Everett R, J Mol Biol. 1994 Mar 25;237(2):201-11. PMID:8126734
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