Pohl F M
Proc Natl Acad Sci U S A. 1986 Jul;83(14):4983-7. doi: 10.1073/pnas.83.14.4983.
The sequence (dC-dG)16, inserted into the polylinker of plasmid pUC8, adopts a left-handed Z-DNA conformation at "natural" supercoil density. The radioactively labeled monoclonal antibody Z-D11, which has a very high affinity for this DNA conformation, provides a convenient sensitive tool to measure selectively the amount of Z-DNA. Chloroquine reversibly changes the supercoil density of plasmid DNA and thereby the equilibrium between right- and left-handed double-helical DNA. The time-dependent formation or disappearance of Z-DNA was measured by using the antibody either as a fast indicator of Z-DNA or as an additional effector of the B-to-Z equilibrium. In the middle of the transition, a relaxation time of about 1 hr is observed in 0.1 M NaCl at 22 degrees C. The kinetic data are compatible with an all-or-none transition between the two conformations. The overall rate constant for Z-DNA formation, kBZ, decreases with the square of the chloroquine concentration, while the reverse one, kZB, increases with about the fourth power.
插入质粒pUC8多克隆位点的序列（dC-dG）16在“天然”超螺旋密度下呈左手Z-DNA构象。对这种DNA构象具有非常高亲和力的放射性标记单克隆抗体Z-D11，提供了一种方便灵敏的工具来选择性地测量Z-DNA的量。氯喹可逆地改变质粒DNA的超螺旋密度，从而改变右手和左手双螺旋DNA之间的平衡。通过将抗体用作Z-DNA的快速指示剂或B-Z平衡的额外效应物来测量Z-DNA随时间的形成或消失。在转变过程中，在22℃的0.1M NaCl中观察到约1小时的弛豫时间。动力学数据与两种构象之间的全或无转变一致。Z-DNA形成的总速率常数kBZ随氯喹浓度的平方而降低，而反向速率常数kZB则随约四次方增加。
