Summary of cap structures detected in liquid chromatography-fractionated sRNA.

Abbreviations: ND, not detected; Nm, ribose methylated ribonucleic acid; mN, base monomethylated ribonucleic acid; 2 mN, base dimethylated ribonucleic acid; 3 mN, base trimethylated ribonucleic acid; Yn, unknown structure 2mGpppAm(1) and 2mGpppAm(2) are isomer with different retention time on LC-MS, which may be 2,2mGpppAm and 2,7mGpppAm. Note that the order of the 5′ end nucleotide is not predictable by mass spectroscopy.

缩写说明：ND表示未检出（not detected）；Nm代表核糖甲基化核糖核酸（ribose methylated ribonucleic acid）；mN代表碱基单甲基化核糖核酸（base monomethylated ribonucleic acid）；2mN代表碱基二甲基化核糖核酸（base dimethylated ribonucleic acid）；3mN代表碱基三甲基化核糖核酸（base trimethylated ribonucleic acid）；Yn代表结构未知产物（unknown structure）。2mGpppAm(1)与2mGpppAm(2)为液相色谱-质谱联用（LC-MS）分析中保留时间存在差异的异构体，二者可能为2,2mGpppAm与2,7mGpppAm。需注意：5'端核苷酸的序列无法通过质谱进行预测。