Banas J A, Ferretti J J, Progulske-Fox A
Department of Microbiology and Immunology, University of Oklahoma Health Sciences Center, Oklahoma City 73190.
Nucleic Acids Res. 1991 Aug 11;19(15):4189-92. doi: 10.1093/nar/19.15.4189.
A gene from the periodontal organism Porphyromonas gingivalis has been identified as encoding a DNA methylase. The gene, referred to as pgiIM, has been sequenced and found to contain a reading frame of 864 basepairs. The putative amino acid sequence of the encoded methylase was 288 amino acids, and shared 47% and 31% homology with the Streptococcus pneumoniae DpnII and E. coli Dam methylases, respectively. The activity and specificity of the pgi methylase (M.PgiI) was confirmed by cloning the gene into a dam- strain of E. coli (JM110) and performing a restriction analysis on the isolated DNA with enzymes whose activities depended upon the methylation state of the DNA. The data indicated that M.PgiI, like DpnII and Dam, methylated the adenine residue within the sequence 5'-GATC-3'.
一种来自牙周病原体牙龈卟啉单胞菌的基因已被鉴定为编码一种DNA甲基化酶。该基因被称为pgiIM，已完成测序，发现其含有一个864个碱基对的阅读框。所编码甲基化酶的推定氨基酸序列为288个氨基酸，分别与肺炎链球菌DpnII甲基化酶和大肠杆菌Dam甲基化酶具有47%和31%的同源性。通过将该基因克隆到大肠杆菌（JM110）的dam-菌株中，并使用其活性取决于DNA甲基化状态的酶对分离的DNA进行限制性分析，证实了pgi甲基化酶（M.PgiI）的活性和特异性。数据表明，M.PgiI与DpnII和Dam一样，使序列5'-GATC-3'中的腺嘌呤残基发生甲基化。
