Perkins D R, Barnum S R
Department of Botany, Miami University, Oxford, Ohio 45056.
Plasmid. 1992 Sep;28(2):170-6. doi: 10.1016/0147-619x(92)90048-f.
The 4194-bp plasmid, pRF1, from Plectonema sp. Strain PCC 6402 was completely sequenced and analyzed. Seven potential open reading frames were identified. The predicted amino acid sequence of open reading frame C (ORF C) had identities of 34, 29, and 25% with Rep B from the Staphylococcus aureus plasmid, pUB110; Rep from the Bacillus amyloliquefaciens plasmid, pFTB14; and protein A from the S. aureus plasmid, pC194, respectively. A 75-amino-acid region conserved in these proteins (Rep B, Rep, and protein A) also was highly conserved in ORF C with identities of 45, 37, and 40%, respectively. Significantly, 16 of the 21 amino acids conserved in Rep B, Rep, and protein A were found at the same positions in ORF C. This ORF may encode a replication protein that includes a region conserved in some eubacteria. Additional structural features include a 425-bp region that contains palindromes, tandem repeats, and short direct repeats which may correspond to the origin of replication. An 18-bp inverted repeat was located between two open reading frames, A and G.
对来自席藻属菌株PCC 6402的4194碱基对质粒pRF1进行了全序列测定和分析。鉴定出7个潜在的开放阅读框。开放阅读框C（ORF C）的预测氨基酸序列与金黄色葡萄球菌质粒pUB110的Rep B、解淀粉芽孢杆菌质粒pFTB14的Rep以及金黄色葡萄球菌质粒pC194的蛋白A的一致性分别为34%、29%和25%。这些蛋白质（Rep B、Rep和蛋白A）中保守的一个75个氨基酸的区域在ORF C中也高度保守，一致性分别为45%、37%和40%。值得注意的是，Rep B、Rep和蛋白A中保守的21个氨基酸中有16个在ORF C的相同位置被发现。这个ORF可能编码一种复制蛋白，该蛋白包含一些真细菌中保守的区域。其他结构特征包括一个425碱基对的区域，其中含有回文序列、串联重复序列和短直接重复序列，这些可能对应于复制起点。一个18碱基对的反向重复序列位于两个开放阅读框A和G之间。
