YxiN is a modular protein combining a DExD/H core and a specific RNA-binding domain
YxiN is a modular protein combining a DExD/H core and a specific RNA-binding domain
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DOI：
10.1074/jbc.m506815200
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发表时间：
2005-10-21
影响因子：
4.8
通讯作者：
Uhlenbeck, OC
中科院分区：
文献类型：
--
作者：
Karginov, FV;Caruthers, JM;Uhlenbeck, OC
DEX（D）/（H）蛋白，通常被描述为RNA解旋酶，参与细胞中RNA-RNA和可能的RNA-蛋白质复合物的重排.除了保守的DEx（D）/（H）核心之外，该蛋白质家族的成员通常含有负责额外功能的N-和C-末端延伸。枯草芽孢杆菌DEx（D）/（H）-盒蛋白YxiN及其大肠杆菌直系同源物DbpA含有类似于80个氨基酸的C-末端延伸，已提出其与包括发夹92的23 S核糖体RNA区域特异性相互作用.在这项研究中，表达了YxiN的DEx（D）/（H）-盒核心和C-末端结构域，并将其表征为单独的蛋白质。分离的DEx（D）/（H）-盒核心YxCat具有弱的非特异性RNA结合活性，并显示出RNA刺激的ATP酶活性，其K-m（ATP）类似于几种非特异性DEx（D）/（H）蛋白。分离的C末端结构域YxRBD以用全长YxiN所见的高亲和力和特异性结合RNA。因此，YxiN是组合了YxCat和YxRBD结构域的活性的模块化蛋白。在23 S rRNA的172个核苷酸片段上的YxiN和YxRBD的足迹被用于鉴定C-末端和解旋酶结构域与RNA的相互作用位点。
DEx(D)/(H) proteins, typically described as RNA helicases, participate in rearrangement of RNA- RNA and possibly RNA- protein complexes in the cell. Aside from the conserved DEx(D)/(H) core, members of this protein family often contain N- and C- terminal extensions that are responsible for additional functions. The Bacillus subtilis DEx(D)/ (H)- box protein YxiN and its Escherichia coli ortholog DbpA contain an similar to 80 amino acid C- terminal extension that has been proposed to specifically interact with a region of 23 S ribosomal RNA including hairpin 92. In this study, the DEx(D)/(H)- box core and the C- terminal domain of YxiN were expressed and characterized as separate proteins. The isolated DEx(D)/(H)- box core, YxCat, had weak, nonspecific RNA binding activity and showed RNA- stimulated ATPase activity with a K-m( ATP) that resembled several nonspecific DEx(D)/(H) proteins. The isolated C- terminal domain, YxRBD, bound RNA with the high affinity and specificity seen with full-length YxiN. Thus, YxiN is a modular protein combining the activities of the YxCat and YxRBD domains. Footprinting of YxiN and YxRBD on a 172- nucleotide fragment of 23 S rRNA was used to identify the sites of interaction of the C- terminal and helicase domains with the RNA.