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What is the function of DNA gyrase quizlet?

DNA gyrase (also referred to as topoisomerase) reduces supercoiling (relaxes tension) which builds up during DNA unwinding, preventing DNA breakage.

What function does gyrase topo II serve in DNA replication?

The first type II topoisomerase (Topo II) to be described was isolated from E. coli. and named DNA gyrase. Topo II enzymes have the ability to cut both strands of a double-stranded DNA molecule, pass another portion of the duplex through the cut, and reseal the cut in a process that utilizes ATP (Figure 12-16a).

What is the purpose of topoisomerase II?

Type II topoisomerases are topoisomerases that cut both strands of the DNA helix simultaneously in order to manage DNA tangles and supercoils.

How do topoisomerase II inhibitors work?

Inhibitors of the mammalian enzymes are widely used antitumor drugs. They stabilize topoisomerase-DNA cleavable complexes by hindering the DNA relegating step of the catalytic reaction, thus resulting in DNA cleavage stimulation.

What are topoisomerase II inhibitors?

Topoisomerase II is an enzyme essential for DNA replication, chromosome condensation and chromosome segregation. Inhibitors of topoisomerase II are important drugs used in the therapy of many neoplasms including breast cancer, lung cancer, testicular cancer, lymphomas and sarcomas.

How do topoisomerases work?

Topoisomerases catalyze and guide the unknotting or unlinking of DNA by creating transient breaks in the DNA using a conserved tyrosine as the catalytic residue. The insertion of (viral) DNA into chromosomes and other forms of recombination can also require the action of topoisomerases.

What happens if there’s no topoisomerase?

Topoisomerase alleviates supercoiling downstream of the origin of replication. In the absence of topoisomerase, supercoiling tension would increase to the point where DNA could fragment. DNA replication could not be initiated because there would be no RNA primer. DNA strands would not be ligated together.

Why is DNA replication important?

DNA replication occurs in all living organisms acting as the most essential part for biological inheritance. This is essential for cell division during growth and repair of damaged tissues, while it also ensures that each of the new cells receives its own copy of the DNA.

What’s the steps of DNA replication?

There are three main steps to DNA replication: initiation, elongation, and termination. In order to fit within a cell’s nucleus, DNA is packed into tightly coiled structures called chromatin, which loosens prior to replication, allowing the cell replication machinery to access the DNA strands.