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DNA packaging and cutting by phage terminases: Control in phage T4 by a synaptic mechanism
Author(s) -
Black Lindsay W.
Publication year - 1995
Publication title -
bioessays
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.175
H-Index - 184
eISSN - 1521-1878
pISSN - 0265-9247
DOI - 10.1002/bies.950171206
Subject(s) - concatemer , biology , dna , phagemid , synapsis , bacteriophage , in vitro recombination , circular bacterial chromosome , genetics , homologous recombination , microbiology and biotechnology , gene , chromosome , dna replication , molecular cloning , genome , peptide sequence , escherichia coli
Abstract Phage DNA packaging occurs by DNA translocation into a prohead. Terminases are enzymes which initiate DNA packaging by cutting the DNA concatemer, and they are closely fitted structurally to the portal vertex of the prohead to form a ‘packasome’. Analysis among a number of phages supports an active role of the terminases in coupling ATP hydrolysis to DNA translocation through the portal. In phage T4 the small terminase subunit promotes a sequence‐specific terminase gene amplification within the chromosome. This link between recombination and packaging suggests a DNA synapsis mechanism by the terminase to control packaging initiation, formally homologous to eukaryotic chromosome segregation.