Relaxosome
Encyclopedia
Relaxosome is the complex of proteins that facilitates plasmids during bacterial conjugation
. The proteins are encoded by the tra gene in the origin of transfer, oriT, region. The most important of these proteins is relaxase
, which is responsible for beginning the conjugation process by cutting at the nic site via transesterification
. This nicking results in a DNA-Protein complex with the relaxosome bound to a single strand of the plasmid DNA and an exposed 3' hydroxyl group. Relaxase also unwinds the plasmid being conjugated with its helicase properties. The relaxosome interacts with integration host factors within the oriT.
Other genes that code for relaxosome components include TraH, which stabilizes the relaxosome's structural formation, TraI, which encodes for the relaxase
protein, TraJ, which recruits the complex to the oriT site, TraK, which increases the 'nicked' state of the target plasmid, and TraY, which imparts single-stranded DNA character on the oriT site. Tra M plays a particularly important role in relaxase interaction by stimulating 'relaxed' DNA formation.
Bacterial conjugation
Bacterial conjugation is the transfer of genetic material between bacterial cells by direct cell-to-cell contact or by a bridge-like connection between two cells...
. The proteins are encoded by the tra gene in the origin of transfer, oriT, region. The most important of these proteins is relaxase
Relaxase
A relaxase is a single-strand DNA transesterase enzyme produced by some prokaryotes and viruses. Relaxases are responsible for site- and strand-specific nicks in double-stranded DNA. Known relaxases belong to the Rolling Circle Replication initiator superfamily of enzymes and fall into two broad...
, which is responsible for beginning the conjugation process by cutting at the nic site via transesterification
Transesterification
In organic chemistry, transesterification is the process of exchanging the organic group R″ of an ester with the organic group R′ of an alcohol. These reactions are often catalyzed by the addition of an acid or base catalyst...
. This nicking results in a DNA-Protein complex with the relaxosome bound to a single strand of the plasmid DNA and an exposed 3' hydroxyl group. Relaxase also unwinds the plasmid being conjugated with its helicase properties. The relaxosome interacts with integration host factors within the oriT.
Other genes that code for relaxosome components include TraH, which stabilizes the relaxosome's structural formation, TraI, which encodes for the relaxase
Relaxase
A relaxase is a single-strand DNA transesterase enzyme produced by some prokaryotes and viruses. Relaxases are responsible for site- and strand-specific nicks in double-stranded DNA. Known relaxases belong to the Rolling Circle Replication initiator superfamily of enzymes and fall into two broad...
protein, TraJ, which recruits the complex to the oriT site, TraK, which increases the 'nicked' state of the target plasmid, and TraY, which imparts single-stranded DNA character on the oriT site. Tra M plays a particularly important role in relaxase interaction by stimulating 'relaxed' DNA formation.