λ噬菌体DNA，甲基化 来源于大肠杆菌 宿主株 W3110

Phage DNA is isolated from infected E. coli, passed through a series of enzymatic steps before final phenol-chloroform extraction. This methylated lambda DNA is not completely digested by Bcl I, Cla I, Mbo I, Mbo II, Taq I or Xba I whereas non-methylated lambda DNA(product number D3654) is only partially cleaved.

Lambda Phage DNA, Methylated from Escherichia coli host strain W3110 has been used:

• in magnetic tweezers measurements
• in the preparation of ³⁵S-labeled DNA
• in the preparation of coupled standards (DNA + RNA)

Lambda Phage DNA, Methylated from Escherichia coli host strain W3110 is suitable for use as a substrate for restriction enzymes. It was used to study the attractive forces between condensed DNA double helix by combining single-molecule magnetic tweezers and osmotic stress. ³⁵S-labeled Lambda Phage DNA, Methylated from Escherichia coli host strain W3110 was also used to standardize a method of measuring dissolved DNA in seawater.

λ 噬菌体有一个二十面体头和一个长尾，末端为单根纤维。在 5′ 末端的两端是互补的 12 个核苷酸的单链序列，它们有助于 DNA 的粘性末端（cos 区）。噬菌体的尾部锁定在宿主外膜受体上，并将噬菌体 DNA 注入细胞。噬菌体将大肠杆菌转化为溶原性状态，其中噬菌体功能受到抑制，并且噬菌体基因组可能长时间保持休眠（原噬菌体）。这种特性在携带负责 CI 表达的 CII 和 CIII 基因的噬菌体中可见。CI 基因中具有 CI 突变的噬菌体能够在规定的温度下保持溶原状态。
用 λ C1857 菌株感染大肠杆菌菌株 W3110 会产生大肠杆菌溶原菌培养物。通过用 pH 8.0 的高盐缓冲液裂解，噬菌体从大肠杆菌细胞沉淀中释放出来。 将粗混合物通过一系列酶促步骤、多个铯梯度，然后用 1 mM Tris-HCl、pH 8.0 和 1 mM 氯化镁对噬菌体 DNA 进行透析。最后用苯酚-氯仿溶液提取 DNA。

独特的限制位点：Apa I、Nae I、Nar I、Nhe I、PaeR7 I、SnaB I、Xba I 和 Xho I。甲基化 lambda 被 Bcl I、Cla I、Mbo I、Mbo II、Taq I 和 Xba I 部分切割。

DNA is supplied in a solution of 10 mM Tris-HCl (pH 8.0), with 1mM EDTA.

一外径（A₂₆₀） 是大约 50 μg DNA