Structure and Dynamics of Adeno-Associated Virus Serotype 1 VP1-Unique N-Terminal Domain and Its Role in Capsid Trafficking
Structure and Dynamics of Adeno-Associated Virus Serotype 1 VP1-Unique N-Terminal Domain and Its Role in Capsid Trafficking
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DOI：
10.1128/jvi.02524-12
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发表时间：
2013-05-01
影响因子：
5.4
通讯作者：
Agbandje-McKenna, Mavis
中科院分区：
文献类型：
--
作者：
Venkatakrishnan, Balasubramanian;Yarbrough, Joseph;Agbandje-McKenna, Mavis
磷脂酶A（2）结构域位于衣壳病毒蛋白VP 1（VP 1u）独特的N端，在细小病毒感染中的重要性已有报道。本研究使用计算方法来表征腺相关病毒（AAV）血清型1至12的VP 1序列，圆二色性和电子显微镜来监测温度诱导的AAV 1衣壳中的构象变化和通过内吞途径运输过程中遇到的pH值。圆二色性也用于监测在pH 7.5下由VP 2和VP 3或VP 1、VP 2和VP 3组装的AAV 6衣壳中的构象变化。VP 1u的预测（计算）和确认（在溶液中）是结构有序的。观察到该VP结构域经历可逆的pH诱导的解折叠/重折叠过程，α-螺旋结构的损失/获得，其不破坏衣壳完整性，并且可能通过其与组装衣壳的其他VP序列相比的等电点差异而促进。这项研究是第一个物理文件的VP 1u区域的构象变化，可能有利于其外部化从衣壳内部感染期间，并建立了事件的顺序，在逃逸的AAV衣壳从内体途中的核。
The importance of the phospholipase A(2) domain located within the unique N terminus of the capsid viral protein VP1 (VP1u) in parvovirus infection has been reported. This study used computational methods to characterize the VP1 sequence for adeno-associated virus (AAV) serotypes 1 to 12 and circular dichroism and electron microscopy to monitor conformational changes in the AAV1 capsid induced by temperature and the pHs encountered during trafficking through the endocytic pathway. Circular dichroism was also used to monitor conformational changes in AAV6 capsids assembled from VP2 and VP3 or VP1, VP2, and VP3 at pH 7.5. VP1u was predicted (computationally) and confirmed (in solution) to be structurally ordered. This VP domain was observed to undergo a reversible pH-induced unfolding/refolding process, a loss/gain of alpha-helical structure, which did not disrupt the capsid integrity and is likely facilitated by its difference in isoelectric point compared to the other VP sequences assembling the capsid. This study is the first to physically document conformational changes in the VP1u region that likely facilitate its externalization from the capsid interior during infection and establishes the order of events in the escape of the AAV capsid from the endosome en route to the nucleus.