MUTAGENIC ANALYSIS OF DOUBLE-STRANDED-RNA ADENOSINE-DEAMINASE, A CANDIDATE ENZYME FOR RNA EDITING OF GLUTAMATE-GATED ION-CHANNEL TRANSCRIPTS

被引:140
作者
LAI, F [1 ]
DRAKAS, R [1 ]
NISHIKURA, K [1 ]
机构
[1] WISTAR INST ANAT & BIOL,PHILADELPHIA,PA 19104
关键词
D O I
10.1074/jbc.270.29.17098
中图分类号
Q5 [生物化学]; Q7 [分子生物学];
学科分类号
071010 ; 081704 ;
摘要
Mutagenic analysis of the substrate binding and catalytic domains of double-stranded RNA (dsRNA) adenosine deaminase (DRADA) was carried out. This nuclear enzyme is likely to be involved in the RNA editing of glutamate-gated ion channels that are essential for fast excitatory neurotransmission in mammalian brain. The deletion of the first or the third of the three dsRNA binding motifs within the substrate binding domain dramatically decreases enzyme activity, whereas the second motif seems to be dispensable. The results indicate that the three motifs are not functionally equivalent in the catalytic action of DRADA. Mutation of the putative zinc coordinating residues, His(910), Cys(966), and Cys(1036), abolished the DRADA activity. Similarly, the Glu(912) residue, predicted to be involved in the proton transfer functions of the enzyme, was found to be indispensable. Our results reinforce the previous proposal that the hydrolytic deamination mechanism of DRADA may be more similar to that of the cytidine deaminases than of adenosine deaminases.
引用
收藏
页码:17098 / 17105
页数:8
相关论文
共 52 条