DNA helicase activity is associated with the replication initiator protein rep of tomato yellow leaf curl geminivirus
DNA helicase activity is associated with the replication initiator protein rep of tomato yellow leaf curl geminivirus
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DOI：
10.1128/jvi.00924-06
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发表时间：
2006-11-01
影响因子：
5.4
通讯作者：
Bernardi, Francoise
中科院分区：
文献类型：
--
作者：
Clerot, Danielle;Bernardi, Francoise
番茄黄化曲叶撒丁岛病毒（TYLCSV）是一种单链DNA病毒，其Rep蛋白是病毒复制所必需的复制起始蛋白。TYLCSV Rep已被分类在与各种细胞活性相关的ATP酶（AAA+ ATP酶）中，在小DNA和RNA病毒复制启动子的超家族3中，其范例成员是猿猴病毒40大T抗原。该家族的成员是DNA或RNA依赖性ATP酶，具有病毒复制所必需的解旋酶活性。AAA+ ATP酶的另一个显著特征是它们的四级结构，通常由六聚体环组成。TYLCSV Rep具有ATP酶活性，但解旋酶活性一直是一个长期存在的问题，解旋酶活性有助于进一步表征双生病毒使用的滚环复制机制。我们目前的结果表明，TYLCSV Rep缺乏121个N-末端氨基酸的解旋酶活性与其他解旋酶的活性相当：3'突出和3'到5'极性解旋的要求，具有一些独特的功能，并具有最小的AAA+ ATP酶结构域。我们还表明，解旋酶活性是依赖于蛋白质的寡聚状态。
The Rep protein of tomato yellow leaf curl Sardinia virus (TYLCSV), a single-stranded DNA virus of plants, is the replication initiator essential for virus replication. TYLCSV Rep has been classified among ATPases associated with various cellular activities (AAA+ ATPases), in superfamily 3 of small DNA and RNA virus replication initiators whose paradigmatic member is simian virus 40 large T antigen. Members of this family are DNA- or RNA-dependent ATPases with helicase activity necessary for viral replication. Another distinctive feature of AAA+ ATPases is their quaternary structure, often composed of hexameric rings. TYLCSV Rep has ATPase activity, but the helicase activity, which is instrumental in further characterization of the mechanism of rolling-circle replication used by geminiviruses, has been a longstanding question. We present results showing that TYLCSV Rep lacking the 121 N-terminal amino acids has helicase activity comparable to that of the other helicases: requirements for a 3' overhang and 3'-to-5' polarity of unwinding, with some distinct features and with a minimal AAA+ ATPase domain. We also show that the helicase activity is dependent on the oligomeric state of the protein.