initiation by N-formylmethionin如何翻译？什么意思？

These structures include nucleic acids that are unique to or more abundant in microbes than in host cells, such as double-stranded RNA found in replicating viruses and unmethylated CpG DNA sequences found in bacteria; features of proteins that are found in microbes, such as initiation by N-formylmethionine, which is typical of bacterial proteins;

这些结构包括微生物中特有的或比宿主细胞中更丰富的核酸，如在复制病毒中发现的双链RNA和在细菌中发现的非甲基化CpG DNA序列；在微生物中发现的蛋白质的特征，如由N-甲酰甲硫氨酸引发，这是细菌蛋白质的典型特征；