Loakes D, Brown D M, Linde S, Hill F
Laboratory of Molecular Biology, Cambridge, UK.
Nucleic Acids Res. 1995 Jul 11;23(13):2361-6. doi: 10.1093/nar/23.13.2361.
3-Nitropyrrole and 5-nitroindole have been assessed as universal bases in primers for dideoxy DNA sequencing and in the polymerase chain reaction (PCR). In contrast to a previous report, we have found that the introduction of more than one 3-nitropyrrole residue at dispersed positions into primers significantly reduced their efficiency in PCR and sequencing reactions. Primers containing 5-nitroindole at multiple dispersed positions were similarly affected; for both bases only a small number of substitutions were tolerated. In PCR experiments neither base, when incorporated into primers in codon third positions, was as effective as hypoxanthine, which was incorporated in six codon third positions in a 20mer oligomer. However, primers containing up to four consecutive 5-nitroindole substitutions performed well in both PCR and sequencing reactions. Consecutive 3-nitropyrrole substitutions were tolerated, but less well in comparable reactions.
3-硝基吡咯和5-硝基吲哚已被评估作为双脱氧DNA测序引物以及聚合酶链反应（PCR）中的通用碱基。与之前的一份报告不同，我们发现，在引物的分散位置引入多个3-硝基吡咯残基会显著降低它们在PCR和测序反应中的效率。在多个分散位置含有5-硝基吲哚的引物也受到类似影响；对于这两种碱基，仅能容忍少量的取代。在PCR实验中，当这两种碱基被掺入到密码子第三位的引物中时，它们的效果都不如次黄嘌呤，在一个20聚体寡聚物中，次黄嘌呤被掺入到六个密码子第三位。然而，含有多达四个连续5-硝基吲哚取代的引物在PCR和测序反应中均表现良好。连续的3-硝基吡咯取代是可以容忍的，但在类似反应中的效果较差。
