Champoux J J
Annu Rev Biochem. 1978;47:449-79. doi: 10.1146/annurev.bi.47.070178.002313.
In eucaryotic cells virtually all of the DNA is complex with proteins to form a unit fiber approximately 100 A in diameter. Chromatin is formed by the higher order coiling of the unit fiber. In procaryotic cells, as exemplified by E. coli, the actual structure of the chromosome is less clear (218), but the discovery of the DNA gyrase raises the possibility that the DNA helix in the cell is maintained in an underwound state. It may be important to consider these structural features of DNA in future biochemical studies on replication, transcription, and recombination. The recent discoveries of the DNA swivelases, the DNA gyrase, and the DNA unwinding enzymes considerably increase our knowledge of DNA biochemistry. As more is learned about these enzymes and their interaction with DNA, the prospects for understanding the details of DNA transcription, DNA recombination, and particularly DNA replication appear to be good.
在真核细胞中，几乎所有的DNA都与蛋白质结合形成直径约100埃的单位纤维。染色质是由单位纤维的高级盘绕形成的。在原核细胞中，以大肠杆菌为例，染色体的实际结构尚不清楚（218），但DNA促旋酶的发现增加了细胞中DNA螺旋处于负超螺旋状态的可能性。在未来关于复制、转录和重组的生化研究中考虑DNA的这些结构特征可能很重要。最近发现的DNA旋转酶、DNA促旋酶和DNA解旋酶大大增加了我们对DNA生物化学的了解。随着对这些酶及其与DNA相互作用的了解越来越多，理解DNA转录、DNA重组，尤其是DNA复制细节的前景似乎很好。
