Demidov V V, Lazurkin Iu S
Mol Biol (Mosk). 1980 Mar-Apr;14(2):448-55.
We studied the kinetics of formaldehyde dissociation from hydroxymethylated amino groups of nitrous bases on native DNA. Compared with monomers, the rate constant of formaldehyde dissociation from such bases integrate in the double helix proved to be 20 times smaller for adenine and 4 times smaller for cytidine within the temperature range of 15 to 40 degrees C. The kinetic pattern suggests that the dissociation of formaldehyde from hydroxymethylated amino groups does not occur in the direction of the base plane nor through a full fluctuational opening of base pairs. It is presumed that formaldehyde dissociation from modified amino groups is due to softer fluctuational changes which however, make it possible for formaldehyde to attack amino groups perpendicularly to the base plane.
我们研究了天然DNA上含氮碱基的羟甲基化氨基中甲醛解离的动力学。与单体相比，在15至40摄氏度的温度范围内，双螺旋结构中此类碱基上甲醛解离的速率常数，腺嘌呤的要小20倍，胞嘧啶的要小4倍。动力学模式表明，甲醛从羟甲基化氨基的解离并非朝着碱基平面方向发生，也不是通过碱基对的完全波动打开来进行。据推测，甲醛从修饰氨基的解离是由于较温和的波动变化，不过，这使得甲醛能够垂直于碱基平面攻击氨基。
