Polymerase translocation with respect to single-stranded nucleic acid: looping or wrapping of primer around a poly(A) polymerase.
Polymerase translocation with respect to single-stranded nucleic acid: looping or wrapping of primer around a poly(A) polymerase.
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相对于单链核酸的聚合酶易位：引物在聚腺苷酸聚合酶周围形成环或包裹。
DOI：
10.1016/j.str.2009.03.012
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发表时间：
2009
期刊：
影响因子：
--
通讯作者：
Gershon,PaulD
中科院分区：
文献类型：
--
作者：
Li,ChangZheng;Li,Huiying;Zhou,Sufeng;Sun,Eric;Yoshizawa,Janice;Poulos,ThomasL;Gershon,PaulD
痘苗病毒蛋白VP55相对于单链核酸连续易位，同时延伸其3'端。在这里，聚合酶-引物相互作用的所有关键位点都被鉴定出来，证明了易位过程中聚腺苷酸化引物在聚合酶周围的包裹或成环。其中一个位点的侧链取代表明其需要尾部延伸超过〜12个核苷酸长度，寡核苷酸结合时观察到的构象变化表明易位过程中存在变构连接。 VP55 结合后 VP39 的构象变化表明，在 VP55-VP39 复合物中，VP39 的 mRNA 5' 帽结合位点关闭。晶体结构显示 PAPase 催化中心没有侧链取代，具有两种金属离子并具有所有已知的反应基团和催化基团，符合磷酰基转移的经典双金属离子机制。
Vaccinia virus protein VP55 translocates continuously with respect to single-stranded nucleic acid while extending its 3′end. Here, all key sites of polymerase-primer interaction were identified, demonstrating the wrapping or looping of polyadenylation primer around the polymerase during translocation. Side-chain substitutions at one of the sites indicated its requirement for tail extension beyond ∼12 nucleotides in length, and conformational changes observed upon oligonucleotide binding suggested allosteric connectivity during translocation. Conformational changes in VP39 upon VP55 binding suggested that, within the VP55-VP39 complex, VP39's mRNA 5′ cap binding site closes. The crystallographic structure showed a PAPase catalytic center without side-chain substitutions, possessing two metal ions and with all known reactive and catalytic groups represented, fitting a classical two-metal ion mechanism for phosphoryl transfer.