Garon C F, Berry K W, Rose J A
Proc Natl Acad Sci U S A. 1972 Sep;69(9):2391-5. doi: 10.1073/pnas.69.9.2391.
A unique form of terminal redundancy has been observed in DNA molecules extracted from several human adenovirus serotypes. Electron microscopic studies reveal that single-stranded circular molecules are formed when native DNA is denatured and then annealed. Temperatures approaching the T(m) of native DNA are required to convert circles to linear molecules, indicating a high degree of self-complementarity between terminal base sequences of DNA strands. Single-stranded circles are not generated if a limited number of nucleotides (2-4%) are removed from the 3' ends of native DNA by digestion with Escherichia coli exonuclease III before denaturation and annealing. The lenght of the redundant segment appears to differ among major serotypic groups, and a possible association between increased length of the redundant segment and increased oncogenic capability of virus serotype is suggested. Evidence for the configuration of the duplex closure region of circular molecules is also presented.
在从几种人类腺病毒血清型中提取的DNA分子中观察到一种独特形式的末端冗余。电子显微镜研究表明，天然DNA变性后再退火会形成单链环状分子。需要接近天然DNA熔点（Tm）的温度才能将环状分子转化为线性分子，这表明DNA链的末端碱基序列之间具有高度的自我互补性。如果在变性和退火之前用大肠杆菌核酸外切酶III消化天然DNA的3'末端，去除有限数量的核苷酸（2-4%），则不会产生单链环状分子。冗余片段的长度在主要血清型组之间似乎有所不同，并且有人提出冗余片段长度增加与病毒血清型致癌能力增强之间可能存在关联。还提供了环状分子双链闭合区域构型的证据。
