Wang A H, Gessner R V, van der Marel G A, van Boom J H, Rich A
Proc Natl Acad Sci U S A. 1985 Jun;82(11):3611-5. doi: 10.1073/pnas.82.11.3611.
In left-handed Z-DNA, consecutive nucleotides along the chain alternate in the syn and anti conformations. Purine residues form the syn conformation readily and up to now all Z-DNA crystal structures have sequences of alternating purines and pyrimidines. However, we find that d(C-G-A-T-C-G) with the cytosines brominated or methylated on C-5 crystallizes as Z-DNA. The structure reveals thymines in syn and adenines in anti conformations. This suggests that Z-DNA may occur in sequences other than those with alternating purine-pyrimidine sequence.
在左手螺旋Z-DNA中，沿着链的连续核苷酸在顺式和反式构象中交替。嘌呤残基很容易形成顺式构象，到目前为止，所有Z-DNA晶体结构都具有嘌呤和嘧啶交替的序列。然而，我们发现5位溴化或甲基化的胞嘧啶的d（C-G-A-T-C-G）以Z-DNA形式结晶。该结构显示胸腺嘧啶处于顺式构象，腺嘌呤处于反式构象。这表明Z-DNA可能出现在除嘌呤-嘧啶交替序列之外的其他序列中。
