Department of Biological Sciences, National University of Singapore, Singapore 117543, Singapore.
J Mol Biol. 2011 Feb 25;406(3):516-26. doi: 10.1016/j.jmb.2010.12.032. Epub 2010 Dec 30.
Hibiscus latent Singapore virus (HLSV) is a rigid rod-shaped plant virus and a new member of the Tobamovirus family. Unlike all other Tobamoviruses, the HLSV genome contains a unique poly(A) tract in its 3' untranslated region. The virion is composed of a monomeric coat protein (CP) unit of 18 kDa, arranged as a right-handed helix around the virus axis. We have determined the structure of HLSV at 3.5 Å by X-ray fiber diffraction and refined it to an R-factor of 0.096. While the overall structure of the HLSV CP resembles that of other Tobamoviruses, there are a few unique differences. There is a kink in the LR helix due to the presence of His122. Also, the adjacent Lys123 may further destabilize the helix by positive charge repulsion, making the kink more pronounced. The His122-Asp88 salt bridge provides significant stability to the loop adjacent to the RR helix. Carboxyl-carboxylate interactions that drive viral disassembly are also different in HLSV. The nucleotide recognition mechanisms for virus assembly between HLSV and ribgrass mosaic virus are similar, but different between tobacco mosaic virus and cucumber green mottle mosaic virus.
芙蓉潜隐新加坡病毒（HLSV）是一种刚性棒状植物病毒，属于烟草花叶病毒科的一个新成员。与其他烟草花叶病毒不同，HLSV 基因组在其 3'非翻译区含有独特的多聚 A 片段。病毒粒子由 18 kDa 的单体外壳蛋白 (CP) 单元组成，以右手螺旋方式围绕病毒轴排列。我们通过 X 射线纤维衍射确定了 HLSV 的结构，分辨率为 3.5Å，并将其精修至 R 因子为 0.096。尽管 HLSV CP 的整体结构类似于其他烟草花叶病毒，但存在一些独特的差异。由于 His122 的存在，LR 螺旋出现了一个拐点。此外，相邻的 Lys123 可能通过正电荷排斥进一步破坏螺旋，使拐点更加明显。His122-Asp88 盐桥为 RR 螺旋附近的环提供了显著的稳定性。驱动病毒解体的羧酸-羧酸相互作用在 HLSV 中也不同。HLSV 和菵草花叶病毒之间的病毒组装的核苷酸识别机制相似，但与烟草花叶病毒和黄瓜绿斑驳花叶病毒不同。
