title: Structural, functional and evolutionary relationships between homing endonucleases and proteins from their host organisms.
abstract: 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.
authors.affiliation: 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.
authors.forename: Gregory K
authors.initials: GK
authors.lastname: Taylor
authors.forename: Barry L
authors.initials: BL
authors.lastname: Stoddard
mesh_terms: D020816:Amino Acid Motifs; D003087:Colicins / Q000737:chemistry; D045643:DNA Repair Enzymes / Q000737:chemistry / Q000502:physiology; D004262:DNA Restriction Enzymes / Q000737:chemistry; D004706:Endodeoxyribonucleases / Q000737:chemistry* / Q000502:physiology; D019143:Evolution, Molecular; D005786:Gene Expression Regulation; D011506:Proteins / Q000737:chemistry
chemical_list: D003087:Colicins; D011506:Proteins; D004706:Endodeoxyribonucleases; D004262:DNA Restriction Enzymes; D045643:DNA Repair Enzymes