Fastrez J
Laboratoire de Biochimie Physique et des Biopolymères, Université Catholique de Louvain, Louvain-la-Neuve, Belgium.
EXS. 1996;75:35-64. doi: 10.1007/978-3-0348-9225-4_3.
Bacteriophage genomes encode lysozymes whose role is to favour the release of virions by lysis of the host cells or to facilitate infection. In this review, the evolutionary relationships between the phage lysozymes are described. They are grouped into several classes: the V-, the G-, the lambda- and the CH-type lysozymes. The results of structure determinations and of enzymological studies indicate that the enzymes belonging to the first two classes, and possibly the third, share common structural elements with C-type lysozymes (eg. hen egg white lysozyme). The proteins of the fourth class, on the other hand, are structurally similar to the S. erythraeus lysozyme. Several phage lysozymes feature a modular construction: besides the catalytic domain, they contain additional domains or repeated motifs presumed to be important for binding to the bacterial walls and for efficient catalysis. The mechanism of action of these enzymes is described and the role of the important amino acid residues is discussed on the basis of sequence comparisons and of mutational studies. The effects of mutations affecting the structure and of multiple mutations are also discussed, particularly in the case of the T4 lysozyme: from these studies, proteins appear to be quite tolerant of potentially disturbing modifications.
噬菌体基因组编码溶菌酶，其作用是通过裂解宿主细胞促进病毒粒子的释放或促进感染。在这篇综述中，描述了噬菌体溶菌酶之间的进化关系。它们被分为几类：V型、G型、λ型和CH型溶菌酶。结构测定和酶学研究结果表明，属于前两类以及可能第三类的酶与C型溶菌酶（如鸡蛋白溶菌酶）具有共同的结构元件。另一方面，第四类蛋白质在结构上与红霉糖多孢菌溶菌酶相似。几种噬菌体溶菌酶具有模块化结构：除催化结构域外，它们还包含其他结构域或重复基序，推测这些结构域或重复基序对于与细菌细胞壁结合和高效催化很重要。描述了这些酶的作用机制，并基于序列比较和突变研究讨论了重要氨基酸残基的作用。还讨论了影响结构的突变和多重突变的影响，特别是在T4溶菌酶的情况下：从这些研究中，蛋白质似乎对潜在的干扰修饰具有相当的耐受性。
