INTERACTIONS OF BLEOMYCIN ANALOGS WITH DEOXYRIBONUCLEIC-ACID AND METAL-IONS STUDIED BY FLUORESCENCE QUENCHING
INTERACTIONS OF BLEOMYCIN ANALOGS WITH DEOXYRIBONUCLEIC-ACID AND METAL-IONS STUDIED BY FLUORESCENCE QUENCHING
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DOI：
10.1021/bi00550a006
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发表时间：
1980-01-01
期刊：
影响因子：
2.9
通讯作者：
CROOKE, ST
中科院分区：
文献类型：
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作者：
HUANG, CH;GALVAN, L;CROOKE, ST
使用荧光猝灭来研究DNA [小牛胸腺、藤黄微球菌、产气荚膜梭菌]在存在和不存在金属离子的情况下与以下博来霉素（BLM）[BLM药物]类似物的相互作用：活性BLM A2、BLM B1“、塔利霉素A（TLM A）、脱酰胺基-BLM A2、在α-位上具有取代的3种活性较低的BLM A2类似物。β-氨基的氨基氨基丙氨酸[甲基磺酰氨基-BLM A2、苄基磺酰氨基-BLM A2、丹磺酰氨基-BLM A2]和2个无活性TLM片段（Wa和Wb）。所有药物均显示20-30%的非离子型DNA诱导的荧光猝灭，但离子型猝灭的程度如下变化：TLM A、Wa和Wb，50-60%; BLM A2，20-25%; BLM B1“和脱酰胺基-BLM A2，<10%; 3 α-BLM A，20-25%; BLM B1”和脱酰胺基-BLM A2，< 10%; 3 α-BLM A，20 - 25%; BLM B1“和脱酰胺基-BLM A2，< 10%。氨基取代的BLM A2类似物，0%。药物的总体DNA断裂活性与任一类型的淬灭程度没有明显的相关性。通过淬灭效应观察到的DNA-药物相互作用不足以产生断裂活性。对α-β的修饰氨基完全消除了离子猝灭，减少了非离子型。除去β-氨基的末端酰胺基团氨基丙氨酸如在脱酰胺-BLM A2中显着降低了离子淬灭; C-末端胺的正电荷的增加增强了离子淬灭。β-氨基丙氨酸和C-末端胺可能是离子型猝灭效应所必需的，这可能与BLM的DNA双链断裂活性有关，因为与BLM A2相比，这种活性在脱酰胺基-BLM A2中非常低。结合分析表明，在高离子强度下，酰胺的去除或末端胺中正电荷的损失对结合常数的影响最小，但使可用结合位点的数量减少了50%。这些残留位点本质上是非离子的。整体猝灭效应显示碱基和序列偏好性与所报道的DNA断裂的GC、GT和TA特异性一致。DNA与Fe（II）或Cu（II）的猝灭效应是加和的。β-巯基乙醇对Fe（II）和Cu（II）诱导的淬灭有不同的影响，对DNA诱导的淬灭影响不大。
Fluorescence quenching was used to study the interactions of DNA [calf thymus, Micrococcus luteus, Clostridium perfringens], in the presence and absence of metal ions, with the following bleomycin (BLM) [antineoplastic drug] analogs: the active BLM A2, BLM B1'', talisomycin A (TLM A), desamido-BLM A2, the 3 less active BLM A2 analogs with a substitution at the .alpha.-amino group of the .beta.-aminoalanine [methylsulfonamido-BLM A2, benzylsulfonamido-BLM A2, dansylsulfonamido-BLM A2], and the 2 inactive TLM fragments (Wa and Wb). All drugs showed a nonionic type DNA-induced fluorescence quenching of 20-30% but varied in the extent of the ionic type of quenching as follows: TLM A, Wa and Wb, 50-60%; BLM A2, 20-25%; BLM B1'' and desamido-BLM A2, < 10%; the 3 .alpha.-amino-substituted BLM A2 analogs, 0%. There is no apparent correlation of the overall DNA breakage activity of drugs with the extent of either type of quenching. DNA-drug interactions as seen by quenching effects are not sufficient for breakage activity. The modification of the .alpha.-amino group completely eliminated the ionic quenching and reduced the nonionic type. The removal of the terminal amide group of the .beta.-aminoalanine as in desamido-BLM A2 markedly reduced the ionic quenching; an increase in the positive charge of the C-terminal amine enhanced the ionic quenching. The .beta.-aminoalanine and the C-terminal amine may be essential for the ionic type of quenching effect, which may be associated with the DNA double-strand breakage activity of BLM since such activity was very low in desamido-BLM A2 in contrast to BLM A2. The binding analysis indicated that at high ionic strength, the removal of the amide or the loss of the positive charge in the terminal amine minimally affected the binding constant but reduced the number of available binding sites by 50%. These residual sites are nonionic in nature. The overall quenching effect showed a base and sequence preference consistent with the reported GC, GT and TA specificity of the DNA breakage. The quenching effects of DNA and Fe(II) or Cu(II) were additive. .beta.-Mercaptoethanol, which showed a differential effect on Fe(II)- and Cu(II)-induced quenching, had little effect on the DNA-induced quenching.