Marchal C, Perrin D, Hedgpeth J, Hofnung M
Proc Natl Acad Sci U S A. 1980 Mar;77(3):1491-5. doi: 10.1073/pnas.77.3.1491.
The lambda receptor is an outer membrane protein from Escherichia coli K-12 lamB, its structural gene, is part of the maltose regulon. We have cloned this gene in a phage so that it is under the control of the lac promoter. The phage was devised in such a way that it can infect lamB mutants and that chromosomal lamB mutations can be transferred to it. In vivo, the lambda receptor is expressed under lac promoter control and is exported normally to the outer membrane, independently of the expression of the other genes of the maltose regulon. In vitro, DNA of the phage allows efficient synthesis of the lamB product. The protein--or pre-lambda-receptor--made in vitro contains an NH2-terminal sequence of about 25 amino acids not found in the lambda receptor. We have detected no inactivation of phage lambda by the pre-lambda-receptor. Conversion of the pre-lambda-receptor to a form that has the apparent molecular weight of the mature lambda receptor was achieved. A lamB mutation that blocks export in vivo also blocks conversion in vitro.
λ受体是来自大肠杆菌K-12的外膜蛋白，其结构基因lamB是麦芽糖调节子的一部分。我们已将该基因克隆到噬菌体中，使其受lac启动子的控制。所设计的噬菌体能够感染lamB突变体，并且染色体lamB突变能够转移到该噬菌体上。在体内，λ受体在lac启动子的控制下表达，并正常输出到外膜，这与麦芽糖调节子其他基因的表达无关。在体外，噬菌体DNA能高效合成lamB产物。体外合成的蛋白质——或前λ受体——含有约25个氨基酸的NH2末端序列，该序列在λ受体中未发现。我们未检测到前λ受体对噬菌体λ的灭活作用。已实现将前λ受体转化为具有成熟λ受体表观分子量的形式。一个在体内阻断输出的lamB突变在体外也会阻断转化。
