Karyagina A S, Lunin V G, Labbé D, Brousseau R, Lau P C, Nikolskaya I I
Institute of BioMedical Chemistry, Moscow, Russia.
Gene. 1995 May 19;157(1-2):93-6. doi: 10.1016/0378-1119(94)00667-h.
Overproduction of the NlaX DNA methyltransferase (M.NlaX) in an Escherichia coli host conferred resistance to SsoII restriction endonuclease (R.SsoII) digestion. This suggested an overlap of sequence specificity between M.NlaX and M.SsoII, the latter of which modifies the internal cytosine of the target sequence 5'-CCNGG-3'. A variant of M.NlaX (M.Sso/Nla), containing an N-terminal extension from M.SsoII, was also enzymatically active. Using deletion analysis, the N-terminal 71 amino-acid residues of M.SsoII were shown to be essential for modification activity.
在大肠杆菌宿主中过量表达NlaX DNA甲基转移酶（M.NlaX）可赋予对SsoII限制性内切酶（R.SsoII）消化的抗性。这表明M.NlaX和M.SsoII之间存在序列特异性重叠，后者修饰靶序列5'-CCNGG-3'中的内部胞嘧啶。包含来自M.SsoII的N端延伸的M.NlaX变体（M.Sso/Nla）也具有酶活性。通过缺失分析表明，M.SsoII的N端71个氨基酸残基对于修饰活性至关重要。
