Crystal structure of the Zalpha domain of the human editing enzyme ADAR1 bound to left-handed Z-DNA
Schwartz, T.; Rould, M.A.; Lowenhaupt, K.; Herbert, A.; Rich, A.
Science 284(5421): 1841-1845
1999
ISSN/ISBN: 0036-8075 PMID: 10364558 Document Number: 508953
The editing enzyme double-stranded RNA adenosine deaminase includes a DNA binding domain, Zalpha, which is specific for left-handed Z-DNA. The 2.1 angstrom crystal structure of Zalpha complexed to DNA reveals that the substrate is in the left-handed Z conformation. The contacts between Zalpha and Z-DNA are made primarily with the "zigzag" sugar-phosphate backbone, which provides a basis for the specificity for the Z conformation. A single base contact is observed to guanine in the syn conformation, characteristic of Z-DNA. Intriguingly, the helix-turn-helix motif, frequently used to recognize B-DNA, is used by Zalpha to contact Z-DNA.