Families of restriction enzymes: an analysis prompted by molecular and genetic data for type ID restriction and modification systems
Families of restriction enzymes: an analysis prompted by molecular and genetic data for type ID restriction and modification systems
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DOI：
10.1093/nar/29.20.4195
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发表时间：
2001-10-15
影响因子：
14.9
通讯作者：
Murray, NE
中科院分区：
文献类型：
--
作者：
Titheradge, AJB;King, J;Murray, NE
目前的遗传和分子证据将大肠杆菌和肠道沙门氏菌的所有已知I型限制和修饰系统置于四个离散家族之一：IA，IB，IC或ID。StySBLI是ID家族的创始成员。编码序列的相似性已将大肠杆菌和肺炎克雷伯氏菌中的限制性酶切系统确定为ID型家族的可能成员。我们目前的互补测试，确认分配EcoR91和KpnAl的ID家庭。StySBLI和EcoR91的HsdS亚基的氨基酸序列的比对鉴定了两个可变区，每个可变区被预测为靶识别结构域（TRD）。与两个TRD一致，StySBLI显示识别二分靶序列，但其中作为甲基化底物的腺嘌呤残基仅间隔6 bp。家庭关系的影响进行了讨论，并提出了证据，扩大了家庭的隶属关系，确定在肠道细菌到广泛的其他属。
Current genetic and molecular evidence places all the known type I restriction and modification systems of Escherichia coli and Salmonella enterica into one of four discrete families: type IA, IB, IC or ID. StySBLI is the founder member of the ID family. Similarities of coding sequences have identified restriction systems in E.coli and Klebsiella pneumoniae as probable members of the type ID family. We present complementation tests that confirm the allocation of EcoR91 and KpnAl to the ID family. An alignment of the amino acid sequences of the HsdS subunits of StySBLI and EcoR91 identify two variable regions, each predicted to be a target recognition domain (TRD). Consistent with two TRDs, StySBLI was shown to recognise a bipartite target sequence, but one in which the adenine residues that are the substrates for methylation are separated by only 6 bp. Implications of family relationships are discussed and evidence is presented that extends the family affiliations identified in enteric bacteria to a wide range of other genera.