Faculty of Bioengineering and Bioinformatics, Moscow State University, Moscow 119991, Russia.
Fungal Biol. 2010 Feb-Mar;114(2-3):151-9. doi: 10.1016/j.funbio.2009.11.004.
Sequences of peptidases with conserved motifs around the active site residues that are characteristic of trypsins (similar to trypsin peptidases, STP) were obtained from publicly-available fungal genomes and related databases. Among the 75 fungal genomes, 29 species of parasitic Ascomycota contained genes encoding STP and their homologs. Searches of non-redundant protein sequences, patented protein sequences, and expressed sequence tags resulted in another 18 STP sequences in 10 fungal species from Ascomycota, Basidiomycota, and Zygomycota. A comparison of fungi species containing STP sequences revealed that almost all are pathogens of plants, animals or fungi. A comparison of the primary structure of homologous proteins, including the residues responsible for substrate binding and specificity of the enzyme, revealed three groups of homologous sequences, all presumably from S1 family: trypsin-like peptidases, chymotrypsin-like peptidases and serine peptidases with unknown substrate specificity. Homologs that are presumably functionally inactive were predicted in all groups. The results in general support the hypothesis that the expression of trypsin-like peptidases in fungi represents a marker of fungal phytopathogenicity. A phylogenetic tree was constructed using peptidase and homolog amino acid sequences, demonstrating that all have noticeable differences and almost immediately deviate from the common root. Therefore, we conclude that the changes that occurred in STP of pathogenic fungi in the course of evolution represent specific adaptations to proteins of their respective hosts, and mutations in peptidase genes are important components of life-style changes and taxonomic divergence.
从公开的真菌基因组和相关数据库中获得了具有活性位点残基保守基序的肽酶序列，这些基序特征类似于胰蛋白酶（trypsins，类似于胰蛋白酶的肽酶，STP）。在 75 个真菌基因组中，29 种寄生子囊菌含有编码 STP 及其同源物的基因。在非冗余蛋白质序列、专利蛋白质序列和表达序列标签的搜索中，又在子囊菌、担子菌和接合菌的 10 种真菌中获得了另外 18 种 STP 序列。对含有 STP 序列的真菌物种的比较表明，几乎所有的真菌都是植物、动物或真菌的病原体。对同源蛋白一级结构的比较，包括负责酶底物结合和特异性的残基，揭示了三组同源序列，所有序列都假定来自 S1 家族：胰蛋白酶样肽酶、糜蛋白酶样肽酶和具有未知底物特异性的丝氨酸肽酶。所有组中都预测到假定功能失活的同源物。结果总体上支持这样的假设，即真菌中胰蛋白酶样肽酶的表达代表了真菌植物病原性的标志。使用肽酶和同源物氨基酸序列构建了系统发育树，表明所有序列都有明显的差异，几乎立即偏离了共同的根。因此，我们得出结论，在进化过程中致病性真菌中 STP 的变化代表了对各自宿主蛋白质的特异性适应，而肽酶基因的突变是生活方式变化和分类学分化的重要组成部分。
