Steiner M, Bläsi U
Institute of Microbiology and Genetics, Vienna, Austria.
Mol Microbiol. 1993 May;8(3):525-33. doi: 10.1111/j.1365-2958.1993.tb01597.x.
The lysis inhibitor protein S107 and the lysis effector protein S105 start at Met codons 1 and 3 of the Lambda S gene, respectively. The antagonistic action of both proteins precisely schedules lysis by formation of a non-specific lesion in the inner membrane through which the Lambda-encoded murein transglycosylase can pass. Here, we show that the main difference between lysis-effector and lysis-inhibitor is the degree by which an energized membrane inhibits either protein from hole formation. To dissect the structural parameters responsible for intrinsic inhibition of both proteins, charged amino acids were replaced proximal to the first putative membrane-spanning region in both S proteins. Our results show that the distribution of amino-terminal charged amino acids as well as the total amino-terminal net charge of S107 and S105 influence their lethal potential. The data are interpreted in terms of a model in which the electrostatic status of the amino-terminus of both S107 and S105 is an important feature affecting their conformational change required for formation of the S-dependent hole.
裂解抑制蛋白S107和裂解效应蛋白S105分别起始于λ噬菌体S基因的第1和第3个甲硫氨酸密码子。这两种蛋白的拮抗作用通过在内膜上形成一个非特异性损伤来精确安排裂解时间，λ噬菌体编码的胞壁质转糖基酶可通过该损伤。在此，我们表明裂解效应蛋白和裂解抑制蛋白之间的主要区别在于能量化的膜抑制两种蛋白形成孔洞的程度。为了剖析负责两种蛋白内在抑制的结构参数，在两种S蛋白中靠近第一个假定跨膜区域的位置替换了带电荷的氨基酸。我们的结果表明，S107和S105氨基末端带电荷氨基酸的分布以及氨基末端的总净电荷会影响它们的致死潜力。这些数据依据一个模型来解释，在该模型中，S107和S105氨基末端的静电状态是影响形成S依赖性孔洞所需构象变化的一个重要特征。
