Spieker R L, Marinkovic S, Sänger H L
Max-Planck-Institut für Biochemie, Abteilung Viroidforschung, Martinsried, Federal Republic of Germany.
Arch Virol. 1996;141(8):1377-86. doi: 10.1007/BF01718241.
A viroid was isolated from symptomless Coleus blumei cultivar (cv) 'Fairway Ruby' plants using the bidirectional PAGE method for analysis of small circular RNA molecules. The viroid was transmitted to viroid-free plants of Coleus blumei cv. 'Scarlet Dragonfly' by mechanical inoculation. Cloning and sequencing revealed that the viroid from the Coleus cv. 'Fairway Ruby' is closely related to the Coleus blumei viroid 3-Bv (CbVd 3-Bv) isolated from the Coleus cv. 'Bienvenue'. Therefore, the new viroid sequence variant has been named Coleus blumei viroid 3-FR (CbVd 3-FR). Coleus blumei viroid 3-FR consists of 364 nucleotides, 202 G + C, 162 A + U with a GC content of 55.5%. The most stable rod-like secondary structure of this viroid has 82 G:C, 50 A:U and 10 G:U base pairs with a minimum free energy of -670.5 kJ/mol (-160.4 kcal/mol). Due to mutations that increase the stability of the rod-like secondary structure, CbVd 3-FR has a lower minimum free energy than CbVd 3-Bv (-598.2 kJ/mol; -143.1 kcal/mol). A base-exchange in the upper strand of the central domain of CbVd 3-FR may stabilize the basal helix of hairpin I.
采用双向聚丙烯酰胺凝胶电泳法分析小环状RNA分子，从无症状的彩叶草品种‘Fairway Ruby’植株中分离出一种类病毒。通过机械接种将该类病毒传播至无类病毒的彩叶草品种‘Scarlet Dragonfly’植株。克隆和测序结果显示，来自彩叶草品种‘Fairway Ruby’的类病毒与从彩叶草品种‘Bienvenue’中分离出的彩叶草类病毒3 - Bv（CbVd 3 - Bv）密切相关。因此，这种新的类病毒序列变体被命名为彩叶草类病毒3 - FR（CbVd 3 - FR）。彩叶草类病毒3 - FR由364个核苷酸组成，其中202个为G + C，162个为A + U，GC含量为55.5%。该类病毒最稳定的棒状二级结构有82个G:C、50个A:U和10个G:U碱基对，最小自由能为 - 670.5 kJ/mol（- 160.4 kcal/mol）。由于发生了增加棒状二级结构稳定性的突变，CbVd 3 - FR的最小自由能比CbVd 3 - Bv（- 598.2 kJ/mol；- 143.1 kcal/mol）更低。CbVd 3 - FR中央结构域上链中的碱基交换可能会稳定发夹I的基部螺旋。
