1xmk

From Proteopedia

Revision as of 13:11, 20 March 2008

The Crystal structure of the Zb domain from the RNA editing enzyme ADAR1

Overview

The Zalpha domains represent a growing subfamily of the winged helix-turn-helix (HTH) domain family whose members share a remarkable ability to bind specifically to Z-DNA and/or Z-RNA. They have been found exclusively in proteins involved in interferon response and, while their importance in determining pox viral pathogenicity has been demonstrated, their actual target and biological role remain obscure. Cellular proteins containing Zalpha domains bear a second homologous domain termed Zbeta, which appears to lack the ability to bind left-handed nucleic acids. Here, we present the crystal structure of the Zbeta domain from the human double-stranded RNA adenosine deaminase ADAR1 at 0.97 A, determined by single isomorphous replacement including anomalous scattering. Zbeta maintains a winged-HTH fold with the addition of a C-terminal helix. Mapping of the Zbeta conservation profile on the Zbeta surface reveals a new conserved surface formed partly by the terminal helix 4, involved in metal binding and dimerization and absent from Zalpha domains. Our results show how two domains similar in fold may have evolved into different functional entities even in the context of the same protein.

Disease

Known diseases associated with this structure: Dyschromatosis symmetrica hereditaria OMIM:[601059]

About this Structure

1XMK is a Single protein structure of sequence from Homo sapiens. Full crystallographic information is available from OCA.

Reference

The crystal structure of the Zbeta domain of the RNA-editing enzyme ADAR1 reveals distinct conserved surfaces among Z-domains., Athanasiadis A, Placido D, Maas S, Brown BA 2nd, Lowenhaupt K, Rich A, J Mol Biol. 2005 Aug 19;351(3):496-507. PMID:16023667

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