Graduate Program in Molecular and Cellular Biology, University of Washington and Division of Basic Sciences, Fred Hutchinson Cancer Research Center, 1100 Fairview Ave. N. A3-025, Seattle, WA 90109, USA.
Nucleic Acids Res. 2012 Jul;40(12):5189-200. doi: 10.1093/nar/gks226. Epub 2012 Mar 9.
Homing endonucleases (HEs) are highly specific DNA-cleaving enzymes that are encoded by invasive DNA elements (usually mobile introns or inteins) within the genomes of phage, bacteria, archea, protista and eukaryotic organelles. Six unique structural HE families, that collectively span four distinct nuclease catalytic motifs, have been characterized to date. Members of each family display structural homology and functional relationships to a wide variety of proteins from various organisms. The biological functions of those proteins are highly disparate and include non-specific DNA-degradation enzymes, restriction endonucleases, DNA-repair enzymes, resolvases, intron splicing factors and transcription factors. These relationships suggest that modern day HEs share common ancestors with proteins involved in genome fidelity, maintenance and gene expression. This review summarizes the results of structural studies of HEs and corresponding proteins from host organisms that have illustrated the manner in which these factors are related.
归巢内切核酸酶（HEs）是高度特异的 DNA 切割酶，由噬菌体、细菌、古菌、原生生物和真核细胞器基因组中的侵入性 DNA 元件（通常是移动的内含子或内肽酶）编码。迄今为止，已经鉴定出六个独特的结构 HE 家族，它们共同跨越四个不同的核酸酶催化基序。每个家族的成员都显示出与来自各种生物体的各种蛋白质的结构同源性和功能关系。这些蛋白质的生物学功能差异很大，包括非特异性 DNA 降解酶、限制内切酶、DNA 修复酶、核酸酶、内含子剪接因子和转录因子。这些关系表明，现代 HEs 与参与基因组保真度、维持和基因表达的蛋白质具有共同的祖先。本综述总结了结构研究的结果，包括宿主生物中的 HEs 和相应蛋白质，这些研究阐明了这些因素之间的关系。
