VISUALIZATION OF DRUG-NUCLEIC ACID INTERACTIONS AT ATOMIC RESOLUTION .7. STRUCTURE OF AN ETHIDIUM DINUCLEOSIDE MONOPHOSPHATE CRYSTALLINE COMPLEX, ETHIDIUM - URIDYLYL(3'-5')ADENOSINE
VISUALIZATION OF DRUG-NUCLEIC ACID INTERACTIONS AT ATOMIC RESOLUTION .7. STRUCTURE OF AN ETHIDIUM DINUCLEOSIDE MONOPHOSPHATE CRYSTALLINE COMPLEX, ETHIDIUM - URIDYLYL(3'-5')ADENOSINE
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DOI：
10.1080/07391102.1984.10507510
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发表时间：
1984-01-01
影响因子：
4.4
通讯作者：
SOBELL, HM
中科院分区：
文献类型：
--
作者：
JAIN, SC;SOBELL, HM
Ethidium forms a crystalline complex with the dinucleoside monophosphate, uridylyl (3''-5'') adenosine (UpA). The complex crystallizes in the monoclinic space group P21 with unit cell dimensions, a = 13.704 .ANG., b = 31.674 .ANG., c = 15.131 .ANG. and .beta. = 113.9.degree.. This light atom structure was solved to atomic resolution and refined by full matrix least squares to a residual of 0.12, using 3034 observed-reflections. The asymmetric unit consists of 2 ethidium molecules, 2 UpA molecules and 19 solvent molecules (a total of 145 non-hydrogen atoms). The 2 UpA molecules are H-bonded together by Watson-Crick type base pairing. Base-pairs in this duplex are separated by 6.7 .ANG.; this reflects intercalative binding by one of the ethidium molecules. The other ethidium molecule stacks on either side of the intercalated base-paired dinucleoside monophosphate, being related by a unit cell translation along the a axis. The conformation of the sugar-phosphate backbone accompanying intercalation had been accurately determined in this analysis, and contains the mixed sugar-puckering pattern C3'' endo (3''-5'') C2'' endo. This same structural feature has been observed in the ethidium-iodoUpA and ethidium-iodoCpG complexes, and exists in 2 additional structures containing ethidium-CpG. These studies confirm earlier sugar-puckering assignments and demonstrate that I covalently bound to the C5 position on uridine or cytosine does not alter the basic sugar-phosphate geometry or the mode of ethidium intercalation in these model studies. This stereochemistry was proposed to explain the intercalation of ethidium (as well as other simple intercalators) into both DNA and into double-helical RNA.
