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花草马赛克病毒逆转录酶的结构和生化表征

Chandrasekaran Prabaharan¹, Małgorzata Figiel¹, Roman H Szczepanowski²

¹Laboratory of Protein Structure, International Institute of Molecular and Cell Biology in Warsaw, Warsaw, Poland.

The Journal of biological chemistry

|July 13, 2024

概括

花草马赛克病毒 (CaMV) 逆转录酶 (RT) 的第一个晶体结构揭示了它作为单体的功能. CaMV RT需要第二个分子进行RNase H活性,与相关酶不同.

科学领域:

生物化学生化学
结构生物学结构生物学
病毒学病毒学

背景情况:

反转录酶 (RTs) 是逆病毒和逆元素复制中的关键酶,具有DNA聚合酶和RNase H活动.
植物病毒家族Caulimoviridae使用RTs进行dSDNA基因组复制,因缺乏整合酶而与逆转录病毒区别开来.
虽然Ty3 RT的特征很好,但对caulimoviral RT的结构和功能数据仍然有限.

研究的目的:

确定白菜花马赛克病毒 (CaMV) 的第一个晶体结构RT.
阐明CaMV RT的功能机制,特别是其聚合酶和RNase H活动.
将CaMV RT的结构和功能与其他相关RT进行比较.

主要方法:

通过X射线晶体学,获得了CaMV RT与RNA/DNA混合体复合的结构.
进行了酶活性测定,以评估依赖RNA的DNA聚合酶,依赖DNA的DNA聚合酶和RNase H功能.
进行了生物化学分析,以调查CaMV RT.的四级结构和功能要求.

主要成果:

晶体结构显示,CaMV RT 与RNA/DNA杂交物形成单体复合物,与二维Ty3 RT不同.
个别的CaMV RT分子表现出完全的DNA聚合酶活性 (依赖RNA和依赖DNA).
RNase H活性需要额外的CaMV RT分子与主要聚合酶竞争酶的短暂关联.

结论:

花草马赛克病毒RT在聚合酶活性过程中表现出独特的单体结构.
对于CaMV RT的RNase H功能来说,需要一个涉及过时二元化的独特机制.
这些发现为caulimoviral RTs的结构功能关系及其与其他RTs的进化关系提供了新的见解.

关键词:

它们属于Caulimoviridae.在X射线晶体学.花草马赛克病毒 (CaMV)植物病毒植物病毒蛋白质核酸复合体蛋白质核酸复合体反向转录酶的作用.

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