Chapman D, Morad I, Kaufmann G, Gait M J, Jorissen L, Snyder L
Department of Biochemistry, Tel Aviv University, Ramat Aviv, Israel.
J Mol Biol. 1988 Jan 20;199(2):373-7. doi: 10.1016/0022-2836(88)90320-8.
Pre-existing host tRNAs are reprocessed during bacteriophage T4 infection of certain Escherichia coli strains. In this pathway, tRNALys is cleaved 5' to the wobble base by anticodon nuclease and is later restored in polynucleotide kinase and RNA ligase reactions. Anticodon nuclease depends on prr, a locus found only in host strains that restrict T4 mutants lacking polynucleotide kinase and RNA ligase; and on stp, the T4 suppressor of prr restriction. stp was cloned and the nucleotide sequences of its wild-type and mutant alleles determined. Their comparison defined an stp open reading frame of 29 codons at 162.8 to 9 kb of T4 DNA (1 kb = 10(3) base-pairs). We suggest that stp encodes a subunit of anticodon nuclease, perhaps one that harbors the catalytic site; while additional subunits, such as a putative prr gene product, impart protein folding environment and tRNA substrate recognition.
在某些大肠杆菌菌株受到噬菌体T4感染期间，宿主原有的转运RNA（tRNA）会被重新加工。在这个途径中，tRNALys在反密码子核酸酶的作用下，在摆动碱基的5'端被切割，随后在多核苷酸激酶和RNA连接酶反应中得以恢复。反密码子核酸酶依赖于prr，prr是一个仅在限制缺乏多核苷酸激酶和RNA连接酶的T4突变体的宿主菌株中发现的基因座；还依赖于stp，即prr限制的T4抑制基因。stp被克隆出来，并测定了其野生型和突变等位基因的核苷酸序列。它们的比较确定了T4 DNA 162.8至9 kb处一个由29个密码子组成的stp开放阅读框（1 kb = 10³个碱基对）。我们认为stp编码反密码子核酸酶的一个亚基，也许是一个含有催化位点的亚基；而其他亚基，如推测的prr基因产物，赋予蛋白质折叠环境和tRNA底物识别能力。
