A FUNCTIONAL DOMAIN OF BACTERIOPHAGE-LAMBDA TERMINASE FOR PROHEAD BINDING
A FUNCTIONAL DOMAIN OF BACTERIOPHAGE-LAMBDA TERMINASE FOR PROHEAD BINDING
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DOI：
10.1016/s0022-2836(84)80005-4
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发表时间：
1984-01-01
影响因子：
5.6
通讯作者：
FEISS, M
中科院分区：
文献类型：
--
作者：
FRACKMAN, S;SIEGELE, DA;FEISS, M
终止酶是一种多功能的蛋白质复合物，参与噬菌体的DNA包装。组装件.终止酶由噬菌体噬菌体的产物gpNu 1和gpA组成。Nu 1和A基因。在DNA包装的早期，末端酶结合到. DNA形成一个复合体，称为复合体I。终止酶是复合物I结合前体所必需的，以形成称为复合物II的DNA：终止酶：前体复合物。终止酶在水解过程中保持与DNA结合。末端酶在包装中的另一个已知作用是在DNA中产生交错的切口，从而产生粘性末端。λ噬菌体21具有与λ噬菌体相同的粘性末端。头基因的。和21显示出部分序列同源性，并且在结构、功能和位置上类似。的末端。和21不可互换。这种特异性至少涉及两种末端酶作用：DNA结合：前体结合。位于21号染色体左端的第1和第2个基因被鉴定为编码21末端酶，gp 1和gp 2分别类似于gpNu 1和gpA。一个分离出噬菌体，. 21杂种33，其是在21个在末端酶基因内。... 21杂合33 DNA和末端酶具有噬菌体21包装特异性，如通过互补和辅助包装研究所确定的。的末端酶。21 hybrid 33需要...用于包装的探头。其中一个确定的位置，在交叉之间。DNA和21个DNA发生杂交，产生杂交噬菌体。... 21杂合体33携带噬菌体211基因和杂合体噬菌体2/A基因。测序21杂合33 DNA显示，它编码的蛋白质在羧基末端与大肠杆菌的羧基末端的38个氨基酸同源。gpA;蛋白质的其余部分与gp 2同源。这些研究的结果定义了在gpA的羧基末端结合prohead的特异性结构域。
Terminase is a multifunctional protein complex involved in DNA packaging during bacteriophage .lambda. assembly. Terminase is made of gpNu1 and gpA, the products of the phage .lambda. Nu1 and A genes. Early during DNA packaging terminase binds to .lambda. DNA to form a complex called complex I. Terminase is required for the binding of proheads by complex I to form a DNA:terminase:prohead complex known as complex II. Terminase remains associated with the DNA during encapsidation. The other known role for terminase in packaging is the production of staggered nicks in the DNA, thereby generating the cohesive ends. Lambdoid phage 21 has cohesive ends identical to those of .lambda.. The head genes of .lambda. and 21 show partial sequence homology and are analogous in structure, function and position. The terminases of .lambda. and 21 are not interchangeable. At least 2 actions of terminase are involved in this specificity:DNA binding:prohead binding. The 1 and 2 genes at the left end of the 21 chromosome were identified as coding for the 21 terminase, gp1 and gp2 are analogous to gpNu1 and gpA, respectively. One isolated a phage, .lambda.-21 hybrid 33, which is the product of a crossover between .lambda. and 21 within the terminase genes. .lambda.-21 hybrid 33 DNA and terminase have phage 21 packaging specificity, as determined by complementation and helper packaging studies. The terminase of .lambda.-21 hybrid 33 requires .lambda. proheads for packaging. One determined the position at which the crossover between .lambda. DNA and 21 DNA occurred to produce the hybrid phage. .lambda.-21 hybrid 33 carries the phage 21 1 gene and a hybrid phage 2/A gene. Sequencing of .lambda.-21 hybrid 33 DNA shows that it encodes a protein that is homologous at the carboxy terminus with the 38 amino acids of the carboxy terminus of .lambda. gpA; the remainder of the protein is homologous to gp2. The results of these studies define a specificity domain for prohead binding at the carboxy terminus of gpA.