Kay V, Bode J
GBF, Gesellschaft für Biotechnologische Forschung mbH, Braunschweig-Stöckheim, Germany.
Biochemistry. 1994 Jan 11;33(1):367-74. doi: 10.1021/bi00167a047.
Scaffold-attached-region (SAR) elements of DNA enhance transcriptional rates, and this has been correlated with their ability to undergo separation into single strands (ssDNA) under conditions of negative superhelicity (Bode et al., 1992). The competition studies presented here suggest that the SAR-scaffold interaction is based, in part, on the recognition of single strands, while about one-half of SAR sites are inaccessible to ssDNA. Conversely, since there are 20,000 SAR sites but more than 60,000 sites for ssDNA per nuclear equivalent, not all ssDNA sites are open for SARs. In addition, a completely separate set of binding centers recognizing and enzymatically converting DNA of superhelical density below -0.04 can be titrated. These findings reflect multiple binding specificities for scaffold preparations that are routinely used for screening scaffold-attached regions.
DNA的支架附着区域（SAR）元件可提高转录速率，这与其在负超螺旋条件下分离为单链（ssDNA）的能力相关（博德等人，1992年）。本文提出的竞争研究表明，SAR与支架的相互作用部分基于对单链的识别，而约一半的SAR位点无法与ssDNA结合。相反，由于每个核当量有20,000个SAR位点，但ssDNA位点超过60,000个，并非所有的ssDNA位点都对SAR开放。此外，一组完全独立的结合中心可被滴定，这些中心能够识别并酶促转化超螺旋密度低于-0.04的DNA。这些发现反映了常用于筛选支架附着区域的支架制剂具有多种结合特异性。
