Adenosine deaminase z-alpha domain

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Adenosine deaminase z-alpha domain
PDB 1xmk EBI.jpg
Crystal structure of the zb domain from the RNA editing enzyme ADAR1
Symbol z-alpha
Pfam PF02295
Pfam clan CL0123
InterPro IPR000607
SCOP 1qgp

In molecular biology, the protein domain Adenosine deaminase z-alpha domain refers to an evolutionary conserved protein domain. This family consists of the N-terminus and thus the z-alpha domain of double-stranded RNA-specific adenosine deaminase (ADAR), an RNA-editing enzyme. The z-alpha domain is a Z-DNA binding domain, and binding of this region to B-DNA has been shown to be disfavoured by steric hindrance.[1]


Double-stranded RNA-specific adenosine deaminase (EC) converts multiple adenosines to inosines and creates I/U mismatched base pairs in double-helical RNA substrates without apparent sequence specificity. DRADA has been found to modify adenosines in AU-rich regions more frequently, probably due to the relative ease of melting A/U base pairs compared to G/C base pairs. The protein functions to modify viral RNA genomes, and may be responsible for hypermutation of certain negative-stranded viruses. DRADA edits the mRNAs for the glutamate receptor subunits by site-selective adenosine deamination. The DRADA repeat is also found in viral E3 proteins, which contain a double-stranded RNA-binding domain.


Genes encoding proteins containing this domain include ADAR and ZBP1.


  1. ^ Schade M, Turner CJ, Kühne R, Schmieder P, Lowenhaupt K, Herbert A, Rich A, Oschkinat H (October 1999). "The solution structure of the Zalpha domain of the human RNA editing enzyme ADAR1 reveals a prepositioned binding surface for Z-DNA". Proc. Natl. Acad. Sci. U.S.A. 96 (22): 12465–70. doi:10.1073/pnas.96.22.12465. PMC 22950Freely accessible. PMID 10535945. 

This article incorporates text from the public domain Pfam and InterPro IPR000607