Mechanism of interferon action: Functionally distinct RNA-binding and catalytic domains in the interferon-inducible, double-stranded RNA-Specific adenosine deaminase
Mechanism of interferon action: Functionally distinct RNA-binding and catalytic domains in the interferon-inducible, double-stranded RNA-Specific adenosine deaminase
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DOI：
10.1128/jvi.70.3.1961-1968.1996
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发表时间：
1996-03-01
影响因子：
5.4
通讯作者：
Samuel, CE
中科院分区：
文献类型：
--
作者：
Liu, Y;Samuel, CE
干扰素诱导的双链RNA特异性腺苷脱氨酶（dsRAD）的1，226个氨基酸序列含有三个拷贝（R（I）、R（II）和R（III））的高度保守的亚结构域R基序，通常在双链RNA结合蛋白中发现。我们已经研究了dsRAD的三个R基序拷贝中的每一个中的等同定点突变对RNA结合活性和腺苷脱氨酶活性的影响。将R基序的突变作为单一突变体单独分析和彼此组合分析。结果表明，R（III）拷贝是dsRAD活性的三个R基序中最重要的，R（II）拷贝是最不重要的。R（III）突变体缺乏可检测的酶活性，并显示出大大减少的RNA结合活性。在假定的C-末端脱氨酶催化结构域的高度保守的CHAE序列内的定点突变破坏酶活性，但不影响RNA结合活性。这些结果表明，RNA结合R亚结构域的三个拷贝可能在功能上彼此不同，并且也与dsRAD的催化结构域不同。
The 1,226-amino-acid sequence of the interferon-inducible double-stranded RNA-specific adenosine deaminase (dsRAD) contains three copies (R(I), R(II), and R(III)) of the highly conserved subdomain R motif commonly found in double-stranded RNA-binding proteins. We have examined the effects of equivalent site-directed mutations in each of the three R-motif copies of dsRAD on RNA-binding activity and adenosine deaminase enzyme activity. Mutations of the R motifs were analyzed alone as single mutants and in combination with each other. The results suggest that the R(III) copy is the most important of the three R motifs for dsRAD activity and that the R(II) copy is the least important. The R(III) mutant lacked detectable enzymatic activity and displayed greatly diminished RNA-binding activity. Site-directed mutations within the highly conserved CHAE sequence of the postulated C-terminal deaminase catalytic domain destroyed enzymatic activity but did not affect RNA-binding activity. These results indicate that the three copies of the RNA-binding R subdomain are likely functionally distinct from each other and also from the catalytic domain of dsRAD.