INTERACTION OF MITHRAMYCIN WITH DNA - EVIDENCE THAT MITHRAMYCIN BINDS TO DNA AS A DIMER IN A RIGHT-HANDED SCREW CONFORMATION
INTERACTION OF MITHRAMYCIN WITH DNA - EVIDENCE THAT MITHRAMYCIN BINDS TO DNA AS A DIMER IN A RIGHT-HANDED SCREW CONFORMATION
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DOI：
10.1111/j.1432-1033.1991.tb16020.x
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发表时间：
1991-06-01
期刊：
影响因子：
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通讯作者：
GARNIERSUILLEROT, A
中科院分区：
文献类型：
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作者：
DEMICHELI, C;ALBERTINI, JP;GARNIERSUILLEROT, A
光神霉素的CD和荧光性质已被用于跟踪其与阳离子如Mg 2+和Zn 2+的络合以及这些络合物与DNA的结合。 在水溶液中的低浓度（< 2 μ M）下，光神霉素总是处于二聚体状态，当二聚体是中性的时，二聚体的构象是右旋螺旋，或者当二聚体带负电荷时，二聚体的构象是左旋螺旋。 在去质子化状态下，二聚体可以结合一个阳离子，形成具有右旋螺旋构象的络合物[M2+（Mit-）2]。 在0.1 M KCl中，37 ℃时该络合物的稳定常数分别为4 × 10（5）和1 × 10（6）（对于Mg 2+和Zn 2+）。 右旋螺旋构象的复合物结合DNA。 在这种情况下，络合物[M2+（Mit-）2]的稳定常数增加，对于Mg 2+和Zn 2+分别为3.6 × 10（6）和1.2 × 10（7）。
The CD and fluorescence properties of mithramycin have been used to follow its complexation to cations such as Mg2+ and Zn2+ and the binding of these complexes to DNA. At low concentration (< 2-mu-M) in aqueous solution, mithramycin is always in the dimeric state, the conformation of the dimer being either a right-handed screw when the dimer is neutral, or a left-handed screw when the dimer is negatively charged. In the deprotonated state the dimer can bind one cation forming a complex [M2+ (Mit-)2] which has a right-handed screw conformation. The stability constants of the complex at 37-degrees-C in 0.1 M KCl are 4 x 10(5) and 1 x 10(6) for Mg2+ and Zn2+, respectively. The complex in the right-handed screw conformation binds DNA. In this case the stability constants of the complex [M2+ (Mit-)2[ increase and are 3.6 x 10(6) and 1.2 x 10(7) for Mg2+ and Zn2+, respectively.