1zu1: Difference between revisions

[[Image:1zu1.gif|left|200px]]

'''Solution Structure of the N-terminal Zinc Fingers of the Xenopus laevis double stranded RNA binding protein ZFa'''

Several zinc finger proteins have been discovered recently that bind specifically to double-stranded RNA. These include the mammalian JAZ and wig proteins, and the seven-zinc finger protein ZFa from Xenopus laevis. We have determined the solution structure of a 127 residue fragment of ZFa, which consists of two zinc finger domains connected by a linker that remains unstructured in the free protein in solution. The first zinc finger consists of a three-stranded beta-sheet and three helices, while the second finger contains only a two-stranded sheet and two helices. The common structures of the core regions of the two fingers are superimposable. Each finger has a highly electropositive surface that maps to a helix-kink-helix motif. There is no evidence for interactions between the two fingers, consistent with the length (24 residues) and unstructured nature of the intervening linker. Comparison with a number of other proteins shows similarities in the topology and arrangement of secondary structure elements with canonical DNA-binding zinc fingers, with protein interaction motifs such as FOG zinc fingers, and with other DNA-binding and RNA-binding proteins that do not contain zinc. However, in none of these cases does the alignment of these structures with the ZFa zinc fingers produce a consistent picture of a plausible RNA-binding interface. We conclude that the ZFa zinc fingers represent a new motif for the binding of double-stranded RNA.

1ZU1 is a [[Single protein]] structure of sequence from [http://en.wikipedia.org/wiki/Xenopus_laevis Xenopus laevis]. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=1ZU1 OCA].  

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