Complex terminal structure of a linear mitochondrial plasmid from Physarum polycephalum: three terminal inverted repeats and an ORF encoding DNA polymerase
Complex terminal structure of a linear mitochondrial plasmid from Physarum polycephalum: three terminal inverted repeats and an ORF encoding DNA polymerase
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多头绒泡菌线性线粒体质粒的复杂末端结构：三个末端反向重复序列和编码 DNA 聚合酶的 ORF
作者：
H. Takano;S. Kawano;T. Kuroiwa
多头绒泡菌的线粒体具有促进线粒体融合的线性质粒（mF）。为了确定mF质粒的末端结构，克隆并测序了来自其末端的限制性片段。测序结果表明，mF质粒具有三种末端反向重复序列（TIR）。最典型的特征是在质粒末端的205-bp TIR和另一个591-bp TIR之间存在144-bp重复单位。所有的克隆显示至少一个这些144-bp的重复单元。205-bp TIR的GC含量（49%）高于其他TIR和另一个测序区域的GC含量（23%）。这种TIR可以基于复杂的内部回文组分形成三种生物学稳定的发夹结构。此外，在mF质粒的右端区域，存在一个开放阅读框（ORF），其覆盖了整个591-bp TIR和144-bp重复单元之一的大部分。该ORF编码一个547个氨基酸的多肽ORF-547，并与其他来源的线性线粒体质粒的推定DNA聚合酶的聚合结构域显示出广泛的同源性。
The mitochondria of Physarum polycephalum have a linear plasmid (mF) which promotes mitochondrial fusion. To determine the terminal structure of the mF plasmid, restriction fragments derived from its ends were cloned and sequenced. The sequences showed that the mF plasmid has three kinds of terminal inverted repeats (TIRs). The most characteristic feature is a 144-bp repeating unit which exists between a 205-bp TIR at the extreme ends of the plasmid and another 591-bp TIR. All of the clones showed at least one of these 144-bp repeating units. The GC content of the 205-bp TIR (49%) was higher than those of the other TIRs and of another sequenced region (23%). This TIR can form three thermodynamically-stable hairpin structures based on complex internal palindromic components. Moreover, in the right terminal region of the mF plasmid, there is an open reading frame (ORF) which covers the entire 591-bp TIR and most of one of the 144-bp repeating units. This ORF encodes a 547-amino-acid polypeptide, ORF-547, and shows extensive homology with the polymerization domain of the putative DNA polymerases of linear mitochondrial plasmids from other sources.
影响因子：
11.1
作者：
V. Zakian
通讯作者：
V. Zakian