Essential interaction between lambdoid phage 21 terminase and the Escherichia coli integrative host factor.
Essential interaction between lambdoid phage 21 terminase and the Escherichia coli integrative host factor.
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羔羊噬菌体 21 终止酶和大肠杆菌整合宿主因子之间的重要相互作用。
DOI：
10.1016/0022-2836(85)90216-5
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发表时间：
1985
影响因子：
5.6
通讯作者：
Sippy,J
中科院分区：
文献类型：
--
作者：
Feiss,M;Frackman,S;Sippy,J
λ形噬菌体21需要大肠杆菌整合宿主因子（IHF）才能生长。具有21 DNA包装特异性的λ-21杂交体也需要IHF。IHF非依赖性（HER）突变体已被分离出来。HER突变定位于211基因的氨基末端。1基因编码21末端酶的小亚基，1多肽的氨基末端的一半是特异性结合21 DNA的功能结构域。因此，末端酶的DNA结合结构域的变化，突变，使21末端酶能够在IHF的情况下发挥作用。用体外系统证明21个DNA的包装是IHF依赖的。IHF在装配的早期、末端依赖性步骤中是直接需要的。结论是IHF是21末端酶功能所需的宿主因子。有人提出，类似于IHF在λ整合中的作用，IHF促进21末端酶与噬菌体DNA的适当结合。与此提议一致，可能的IHF结合位点存在于21粘性末端位点。
Lambdoid phage 21 requires theEscherichia coliintegrative host factor (IHF) for growth. λ-21 hybrids that have 21 DNA packaging specificity also require IHF. IHF-independent (her) mutants have been isolated.hermutations map in the amino-terminal half of the 21 1 gene. The 1 gene encodes the small subunit of the 21 terminase, and the amino-terminal half of the 1 polypeptide is a functional domain for specifically binding 21 DNA. Hence changes in the DNA-binding domain of terminase,hermutations, render 21 terminase able to function in the absence of IHF. Three of fourhermutations studied aretrans-dominant.Anin vitrosystem was used to show that packaging of 21 DNA is IHF-dependent. IHF is directly required during the early, terminase-dependent steps of assembly. It is concluded that IHF is a host factor required for function of the 21 terminase. It is proposed, in analogy to the role of IHF in λ integration, that IHF facilitates proper binding of 21 terminase to phage DNA. Consistent with this proposal, possible IHF-binding sites are present in the 21 cohesive end site.