Roof W D, Young R
Department of Biochemistry and Biophysics, Texas A&M University, College Station 77843-2128, USA.
FEMS Microbiol Rev. 1995 Aug;17(1-2):213-8. doi: 10.1111/j.1574-6976.1995.tb00204.x.
Recessive mutations in the slyD (sensitivity to lysis) gene were isolated by selecting for survival after induction of the cloned lysis gene E of bacteriophage phi X174 [1]. The slyD- mutation, transduced into the normal phi X174 host, Escherichia coli C, confers an absolute block on the plaque-forming ability of the wild-type phage, indicating that slyD is required for E function. slyD encodes a protein with 196 residues. A segment corresponding to the first 142 residues of the predicted SlyD protein has significant similarity throughout its length to the FKBP family of peptidyl-prolyl cis-trans isomerases, or rotamases. The C-terminal 46 codons of slyD encode a remarkable histidine-rich peptide which is a metal-binding domain [2]. This sequence is dispensable for slyD function in E-mediated lysis. Although there is no obvious phenotype associated with the slyD- genotype other than the resistance to E-mediated lysis, overexpression of slyD causes cells to filament and to increase significantly in diameter. Mutations in phi X174 can restore the plaque-forming ability of the phage on a slyD- host. These pos (plates on slyD) mutants plate on E. coli C wild-type and slyD-. A model for SlyD involvement in E function and the role of SlyD in the cell is discussed.
通过在诱导噬菌体φX174的克隆裂解基因E后选择存活来分离slyD（对裂解敏感）基因中的隐性突变[1]。将slyD - 突变转导到正常的φX174宿主大肠杆菌C中，会对野生型噬菌体的噬菌斑形成能力产生绝对阻断，这表明slyD是E功能所必需的。slyD编码一种含有196个残基的蛋白质。与预测的SlyD蛋白的前142个残基相对应的一段序列在其全长范围内与肽基 - 脯氨酰顺反异构酶或旋转异构酶的FKBP家族具有显著相似性。slyD的C末端46个密码子编码一个显著富含组氨酸的肽段，它是一个金属结合结构域[2]。该序列对于slyD在E介导的裂解中的功能是可有可无的。尽管除了对E介导的裂解具有抗性外，slyD - 基因型没有明显的表型，但slyD的过表达会导致细胞形成丝状体并使其直径显著增加。φX174中的突变可以恢复噬菌体在slyD - 宿主上的噬菌斑形成能力。这些pos（在slyD上形成噬菌斑）突变体可以在大肠杆菌C野生型和slyD - 菌株上形成噬菌斑。本文讨论了SlyD参与E功能的模型以及SlyD在细胞中的作用。
