Lancelot G, Hélène C
Proc Natl Acad Sci U S A. 1977 Nov;74(11):4872-5. doi: 10.1073/pnas.74.11.4872.
The interaction of carboxylate ions (acetate, butyrate) with nucleic aicd bases and nucleosides has been investigated by proton magnetic resonance in dimethyl sulfoxide (d6)/H2O mixtures. Carboxylate ions interacted only with guanine derivatives and led to a large downfield shift of the NH2 resonance. A 1:1 stoichiometry was deduced from a study of the concentration dependence of chemical shifts. A study of substituted guanine showed that hydrogen bonding involved N(1)H and NH2(2). An association constant of 110 M-1 was determined. This value is about 30 times higher than the association constant for guanine-cytosine base pair formation under the same experimental conditions. As a matter of fact, carboxylate ions induced a dissociation of guanine-cytosine base pairs. This guanine-carboxylate association is experimental evidence for a highly specific interaction that could play an important role in protein/nucleic acid recognition.
通过在二甲亚砜（d6）/H2O混合物中进行质子磁共振研究了羧酸根离子（乙酸根、丁酸根）与核酸碱基和核苷的相互作用。羧酸根离子仅与鸟嘌呤衍生物相互作用，并导致NH2共振发生大幅向低场位移。通过对化学位移浓度依赖性的研究推断出化学计量比为1:1。对取代鸟嘌呤的研究表明，氢键涉及N(1)H和NH2(2)。测定的缔合常数为110 M-1。该值比在相同实验条件下鸟嘌呤-胞嘧啶碱基对形成的缔合常数高约30倍。事实上，羧酸根离子诱导了鸟嘌呤-胞嘧啶碱基对的解离。这种鸟嘌呤-羧酸盐缔合是一种高度特异性相互作用的实验证据，该相互作用可能在蛋白质/核酸识别中起重要作用。
