Hydroxyl radical footprinting of calicheamicin. Relationship of DNA binding to cleavage.
Hydroxyl radical footprinting of calicheamicin. Relationship of DNA binding to cleavage.
复制标题
加利车霉素的羟基自由基足迹。
DOI：
10.1021/bi00168a029
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发表时间：
1994
期刊：
影响因子：
2.9
通讯作者：
Tullius,TD
中科院分区：
文献类型：
--
作者：
Mah,SC;Townsend,CA;Tullius,TD
摘要：用羟基自由基足迹法研究了二芳基抗肿瘤抗生素Calicheamicin 711(CLM711)的重排和还原产物Calicheamicin*(CLM*)与DNA的结合。用这种方法确定的药物结合位点与硫醇激活的CLM711切割双链DNA的位置进行了比较。这些实验的结果表明，CLM*位于延伸的构象中的小凹槽中，保护每条DNA链上大约四个核苷酸。CLM*结合位点与CLM711裂解位点相关，CLM*的保护作用主要发生在C5‘抽氢位点的V侧。根据这些结果，有可能提出药物/DNA复合体的全局结构，使得寡糖侧链排列在C5‘氢提取位置的3’侧。这一结论与最近的原子转移实验结果完全一致[Hangeland，J.J.，de Voss，J.J.，Heath，J.A.，Townsen，C.A.，Ding，W.-D.，Ashcroft，J.，&Ellestad，G.A.(1992)J.Am化学。SoC。114、9200-9202]。对正在进行C5‘氢提取的链的保护作用在攻击部位的5’侧被观察到，这可能是由于药物的氨基甲酸甲酯部分与DNA接近。总体而言，在切割与药物结合的热力学相一致的地方可以看到结合，DNA在确定切割位置时是重要的。
Revised Manuscript Received November 1, 1993® abstract: The binding to DNA by calicheamicin*(CLM*), the rearranged and reduced product of the diynene antitumor antibiotic calicheamicin 711 (CLM711), was studied using the method of hydroxyl radical footprinting. The drug binding sites determined in this way were compared to locations of double-stranded DNA cleavage by thiol-activated CLM711. The results of these experiments show that CLM* lies in the minor groove in an extended conformation protecting approximatelyfour nucleotides on each strand of DNA. Sites of CLM* binding correlate to sites of CLM711 cleavage with protection by CLM* occurring mainly to the V side of the site of C5'hydrogen abstraction. From these results, it is possibleto propose global structures of the drug/DNA complexes such that the oligosaccharide side chain is arrayed to the 3'side of the site of C5'hydrogen abstraction. This conclusion is entirely consistent with the results of recent atom-transfer experiments [Hangeland, J. J., De Voss, J. J., Heath, J. A., Townsend, C. A., Ding, W.-D., Ashcroft, J., & Ellestad, G. A.(1992) J. Am. Chem. Soc. 114, 9200-9202]. Somewhat greater protection on the strand undergoingC5'hydrogen abstraction was observed to the 5'side of the site of attack owing presumably to proximity of the methyl carbamate portion of the drug with DNA. Overall, binding is seen where cleavage is seen in accord with thermodynamics of drug associationto DNA being important in determining the sites of cleavage.