Sanford D G, Stollar B D
Department of Biochemistry, Tufts University School of Medicine, Boston, Massachusetts 02111.
J Biol Chem. 1990 Oct 25;265(30):18608-14.
Two monoclonal anti-Z-DNA antibodies, Z22 and Z44, were shown to bind to the oligonucleotides, d(CG)2 and d(CG)3, and to interact with different parts of the helix. 1H nuclear magnetic resonance spectroscopy showed that Fab fragments stabilize an ordered structure in the tetranucleotide d(CG)2. Nuclear Overhauser effects measured in the presence of Z22 Fab indicate a syn conformation of guanine residues of d(CG)2. Intermolecular transfer of saturation between the Fabs and bound d(CG)3 was detected by a saturation of the protein spectrum and observation of changes in the DNA spectrum. Antibodies with deuterated aromatic amino acids were prepared to eliminate the protein aromatic resonances and thereby allow a more detailed analysis of the transfer to the DNA base protons. The greatest transfer with Z44 was to the dC-5 protons although all of the base protons interact with this antibody. Little, if any, transfer to the DNA base protons was observed with Z22. These results are consistent with a Z44 binding site on the convex surface of the Z-helix (analogous to the major groove of B-DNA) and a Z22 binding site on the sugar-phosphate backbone.
两种单克隆抗Z-DNA抗体Z22和Z44已被证明能与寡核苷酸d(CG)2和d(CG)3结合，并与螺旋的不同部分相互作用。1H核磁共振光谱表明，Fab片段能稳定四核苷酸d(CG)2中的有序结构。在Z22 Fab存在下测量的核Overhauser效应表明d(CG)2的鸟嘌呤残基呈顺式构象。通过蛋白质谱的饱和以及观察DNA谱的变化，检测到Fabs与结合的d(CG)3之间的饱和分子间转移。制备了带有氘代芳香族氨基酸的抗体，以消除蛋白质的芳香族共振，从而更详细地分析向DNA碱基质子的转移。Z44的最大转移是到dC-5质子，尽管所有的碱基质子都与这种抗体相互作用。用Z22观察到向DNA碱基质子的转移很少（如果有的话）。这些结果与Z44在Z-螺旋凸面（类似于B-DNA的大沟）上的结合位点以及Z22在糖-磷酸主链上的结合位点一致。
