title: Promiscuous restriction is a cellular defense strategy that confers fitness advantage to bacteria.
abstract: Most bacterial genomes harbor restriction-modification systems, encoding a REase and its cognate MTase. On attack by a foreign DNA, the REase recognizes it as nonself and subjects it to restriction. Should REases be highly specific for targeting the invading foreign DNA? It is often considered to be the case. However, when bacteria harboring a promiscuous or high-fidelity variant of the REase were challenged with bacteriophages, fitness was maximal under conditions of catalytic promiscuity. We also delineate possible mechanisms by which the REase recognizes the chromosome as self at the noncanonical sites, thereby preventing lethal dsDNA breaks. This study provides a fundamental understanding of how bacteria exploit an existing defense system to gain fitness advantage during a host-parasite coevolutionary "arms race."
authors.affiliation: Department of Microbiology and Cell Biology,  Indian Institute of Science, Bangalore 560012,  India.
authors.forename: Kommireddy
authors.initials: K
authors.lastname: Vasu
authors.forename: Easa
authors.initials: E
authors.lastname: Nagamalleswari
authors.forename: Valakunja
authors.initials: V
authors.lastname: Nagaraja
mesh_terms: D001435:Bacteriophages / Q000235:genetics / Q000378:metabolism*; D005075:Biological Evolution; D015280:DNA Restriction-Modification Enzymes / Q000378:metabolism*; D015252:Deoxyribonucleases, Type II Site-Specific / Q000235:genetics / Q000378:metabolism*; D004591:Electrophoresis, Polyacrylamide Gel; D004926:Escherichia coli / Q000235:genetics / Q000378:metabolism; D056084:Genetic Fitness / Q000235:genetics*; D054884:Host-Pathogen Interactions; D007711:Klebsiella pneumoniae / Q000201:enzymology* / Q000821:virology*; D009841:Oligonucleotides / Q000235:genetics
chemical_list: D015280:DNA Restriction-Modification Enzymes; D009841:Oligonucleotides; D015252:Deoxyribonucleases, Type II Site-Specific; C029312:GGTACC-specific type II deoxyribonucleases