What is Catenation in DNA?

What is Catenation in DNA?

Catenation. Catenation is the process by which two circular DNA strands are linked together like chain links. This occurs after DNA replication, where two single strands are catenated and can still replicate but cannot separate into the two daughter cells.

Why is Decatenation necessary after DNA replication?

Although DNA catenanes are natural intermediates in the process of DNA replication of circular DNA molecules, it is necessary that they become very efficiently decatenated, as otherwise the segregation of freshly replicated DNA molecules would be blocked.

What is Decatenation?

Decatenation. 1. (Science: chemistry) The unlinking of chemical elements within a ring or chain from each other. 2. The unlinking of identical units in a large molecule from each other.

Why is Decatenation important?

The decatenation checkpoint guards against nondisjunction and chromosome breakage that occur when the cell enters mitosis before the chromosomes have been sufficiently decatenated by Topo II.

How Decatenation takes place during the events of bacterial replication?

Decatenation of replicated chromosomes When the last turn of parental DNA duplex is unwound, the daughter molecules end up catenated via one interwinding (Figure 1F). In addition, any pre-catenanes are automatically converted into catenanes9.

How are catenated molecules generated?

It is concluded that catenances are formed by an event associated with replication rather than by recombination and that replication of a monomeric molecule results in the formation of two monomeric molecules or a catenane.

What is meant by Replisome?

Definition. The replisome is a large protein complex that carries out DNA replication, starting at the replication origin. It contains several enzymatic activities, such as helicase, primase and DNA polymerase and creates a replication fork to duplicate both the leading and lagging strand.

What does topoisomerase IV do in DNA replication?

Topoisomerase IV (Topo IV), an essential ATP-dependent bacterial type II topoisomerase, transports one segment of DNA through a transient double-strand break in a second segment of DNA. In vivo, Topo IV unlinks catenated chromosomes before cell division and relaxes positive supercoils generated during DNA replication.

What is bacterial topoisomerase?

Topoisomerases (or DNA topoisomerases) are enzymes that participate in the overwinding or underwinding of DNA. Topoisomerases are isomerase enzymes that act on the topology of DNA. Bacterial topoisomerases and human topoisomerases proceed via similar mechanisms for managing DNA supercoils.