Momynaliev K T, Rogov S I, Govorun V M
Mol Biol (Mosk). 2005 Nov-Dec;39(6):945-51.
Comparison of open-reading frames (ORFs) H. pylori 26695 and J99 strains has been revealed prevalence of nucleotide replacements as transitions (more than 3%) above transversions (less than 1%). Prevalence of nucleotide transitions is caused by high speed of C : G to T : A transitions in a coding strand of DNA (3.5-5.3%) and not coding strand (2.9-3.9%). The correspondence rate of transversion (A --> C, A --> T, C --> A, C --> G, G --> C, G --> T, T --> A and T --> G) did not exceed 0.84%. The highest correspondence frequency between C and T was detected in ACGT-ATGT (28.3%) - the site of methylation by active methyltransferase M.Hpy99XI in H. pylori 26695 and J99. Thus one can speculate that predominant transition taking place in H. pylori is mutation of C into T, which is realized through cytosine methylation-deamination mechanism.
对幽门螺杆菌26695株和J99株的开放阅读框（ORF）进行比较后发现，核苷酸替换中转换（超过3%）的发生率高于颠换（低于1%）。核苷酸转换的发生率是由DNA编码链（3.5 - 5.3%）而非编码链（2.9 - 3.9%）中C:G到T:A转换的高速度所导致。颠换（A→C、A→T、C→A、C→G、G→C、G→T、T→A和T→G）的对应率不超过0.84%。在ACGT - ATGT（28.3%）中检测到C和T之间的最高对应频率，ACGT - ATGT是幽门螺杆菌26695和J99中活性甲基转移酶M.Hpy99XI的甲基化位点。因此可以推测，幽门螺杆菌中发生的主要转换是C突变为T，这是通过胞嘧啶甲基化 - 脱氨机制实现的。
