Sauer R T, Krovatin W, DeAnda J, Youderian P, Susskind M M
J Mol Biol. 1983 Aug 25;168(4):699-713. doi: 10.1016/s0022-2836(83)80070-9.
The DNA sequence of the immI immunity region of bacteriophage P22 has been determined. This region includes the ant gene, which encodes the P22 antirepressor protein, and the mnt and arc genes, which encode proteins that negatively regulate antirepressor synthesis. We have purified antirepressor protein and selected tryptic peptides of antirepressor, and have determined the amino terminal sequences and amino acid composition of these molecules. These data, in combination with the DNA sequence, locate the ant gene and define the complete amino acid sequence of antirepressor (300 residues). The mnt and arc genes have been located by sequencing the mnt-am343 and arc-amH1605 mutations. The Mnt and Arc proteins are predicted to be small, basic polypeptides that are homologous in amino acid sequence. The Mnt protein also shows significant sequence homology with the lambda Cro protein. The arc and ant genes are transcribed rightward from the Pant promoter, while mnt is transcribed leftward from a promotor that may overlap Pant. The Mnt protein apparently acts by binding to an operator site located immediately adjacent to the startpoint of Pant transcription.
噬菌体P22免疫区域immI的DNA序列已被确定。该区域包括编码P22抗阻遏蛋白的ant基因，以及编码负调控抗阻遏蛋白合成的蛋白的mnt和arc基因。我们已纯化抗阻遏蛋白并筛选出抗阻遏蛋白的胰蛋白酶肽段，还确定了这些分子的氨基末端序列和氨基酸组成。这些数据与DNA序列相结合，确定了ant基因的位置并明确了抗阻遏蛋白的完整氨基酸序列（300个残基）。通过对mnt - am343和arc - amH1605突变进行测序，确定了mnt和arc基因的位置。预测Mnt和Arc蛋白是氨基酸序列同源的小碱性多肽。Mnt蛋白与λCro蛋白在序列上也有显著同源性。arc和ant基因从Pant启动子向右转录，而mnt从一个可能与Pant重叠的启动子向左转录。Mnt蛋白显然通过与紧邻Pant转录起始点的一个操纵位点结合来发挥作用。
