Krugh T R, Mooberry E S, Chiao Y C
Biochemistry. 1977 Feb 22;16(4):740-7. doi: 10.1021/bi00623a028.
The proton magnetic resonance spectra of actinomycin solutions with mixtures of deoxynucleotides have been investigated to determine the relative preference for the binding of guanine and adenine nucleotides to the two nucleotide binding sites of actinomycin D. An analysis of the chemical shifts of the actinomycin D resonances shows that adenine and guanine nucleotides competitively bind to the benzenoid portion of the phenoxazone ring of actinomycin D while guanine nucleotides bind stronger than adenine nucleotides to the quinoid portion of the phenoxazone ring. The chemical shift data for the titrations of actinomycin D with pdG-dG, pdC-dC, and an equimolar mixture of these complementary deoxydinucleotides show that: (1) pdG-dG forms a stacked complex much like dGMP; (2) pdC-dC does not bind to actinomycin D under the conditions used in these experiments; (3) in the titration of actinomycin D with the equimolar mixture of pdG-dG + pdC-dC, a miniature intercalated complex is formed.
已对放线菌素溶液与脱氧核苷酸混合物的质子磁共振谱进行了研究，以确定鸟嘌呤和腺嘌呤核苷酸与放线菌素D的两个核苷酸结合位点结合的相对偏好性。对放线菌素D共振化学位移的分析表明，腺嘌呤和鸟嘌呤核苷酸竞争性地结合到放线菌素D吩恶嗪环的苯环部分，而鸟嘌呤核苷酸比腺嘌呤核苷酸更牢固地结合到吩恶嗪环的醌环部分。用pdG-dG、pdC-dC以及这些互补脱氧二核苷酸的等摩尔混合物对放线菌素D进行滴定的化学位移数据表明：（1）pdG-dG形成了一个类似于dGMP的堆积复合物；（2）在这些实验所用条件下，pdC-dC不与放线菌素D结合；（3）在用pdG-dG + pdC-dC等摩尔混合物滴定放线菌素D时，形成了一个微型插入复合物。
