尿嘧啶5-烷基取代对聚[d(A-r5U)]共聚物热稳定性的影响。
Effect of 5-alkyl substitution of uracil on the thermal stability of poly [d(A-r5U)] copolymers.
作者信息
Sági J, Brahms S, Brahms J, Otvös L
出版信息
Nucleic Acids Res. 1979 Jun 25;6(8):2839-48. doi: 10.1093/nar/6.8.2839.
The thermal transition of poly[d(A-r5U)] polydeoxynucleotides (where r was a hydrogen atom, or a methyl, ethyl, n-propyl, n-butyl or n-pentyl group) was studied by measuring the derivative melting profiles of the polymers in the range of 0.01--0.36 M K+, at pH 6.8. According to the Tm values, polydeoxynucleotide analogues show lower thermal stability than poly[d(A-T)] at any counterion concentration applied. At a given salt concentration, Tm of the alkyl analogues decreased as the number of carbon atoms (n) in the r substituent of poly[d(A-r5U)] increased. 1/Tm plotted against against 1/n yielded a linear relationship. Cooperativity of the melting of all poly[d(A--U)] analogues decreased with the increase of salt concentration in the solution. This change depended again on 5-substitution of the uracil moiety of poly[d(A-U)]. Smallest decrease was observed in the case of poly[d(A--U)] whereas largest decrease was shown by poly[d(A-pe5U)] (pe=pentyl group).
通过测量聚合物在0.01 - 0.36 M K⁺范围内、pH 6.8条件下的导数熔解曲线，研究了聚[d(A - r5U)]聚脱氧核苷酸（其中r为氢原子、甲基、乙基、正丙基、正丁基或正戊基）的热转变。根据熔解温度（Tm）值，在任何所施加的抗衡离子浓度下，聚脱氧核苷酸类似物的热稳定性均低于聚[d(A - T)]。在给定的盐浓度下，聚[d(A - r5U)]的r取代基中碳原子数（n）增加时，烷基类似物的Tm降低。以1/Tm对1/n作图得到线性关系。所有聚[d(A - U)]类似物的熔解协同性随溶液中盐浓度的增加而降低。这种变化同样取决于聚[d(A - U)]尿嘧啶部分的5 - 取代情况。聚[d(A - U)]的情况下观察到的降低最小，而聚[d(A - pe5U)]（pe = 戊基）表现出的降低最大。
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