What is the role of the sliding clamp during replication? It keeps DNA polymerase attached to the template while the polymerase synthesizes a new strand of DNA . In the absence of the sliding clamp, most DNA polymerase molecules would synthesize only a short segment of DNA before falling off the template strand.
What is the role of the sliding clamp in DNA replication?
The sliding clamp is a ring-shaped protein that encircles duplex DNA, binds to the DNA polymerase and tethers it to the DNA template, preventing its dissociation and providing high processivity .
Why is a sliding DNA clamp important in DNA replication?
A DNA clamp, also known as a sliding clamp or β-clamp, is a protein complex that serves as a processivity-promoting factor in DNA replication . As a critical component of the DNA polymerase III holoenzyme, the clamp protein binds DNA polymerase and prevents this enzyme from dissociating from the template DNA strand.
Why is a clamp loader necessary in replication?
Clamp loaders are pentameric ATPases of the AAA+ family that operate to ensure processive DNA replication . They do so by loading onto DNA the ring-shaped sliding clamps that tether the polymerase to the DNA.
What is the function of clamp loader?
Clamp loaders are members of the AAA+ family of ATPases and use energy from ATP binding and hydrolysis to catalyze the mechanical reaction of loading clamps onto DNA . Many structural and functional features of clamps and clamp loaders are conserved across all domains of life.
What are the 5 enzymes involved in DNA replication?
The enzymes involved in the replication of prokaryotic DNA are DNA polymerase I to III, helicase, ligase, primase, sliding clamp, topoisomerase, and single-strand binding proteins (SSBs) .
What type of enzyme fills in the gap after damaged DNA has been removed?
| Question Answer | 28) What type of enzyme removes damaged DNA from the rest of the DNA molecules? Nuclease | 29) What type of enzyme fills in the gap after damaged DNA has been removed? Polymerase |
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Is Primer RNA or DNA?
A primer is a short nucleic acid sequence that provides a starting point for DNA synthesis. In living organisms, primers are short strands of RNA . A primer must be synthesized by an enzyme called primase, which is a type of RNA polymerase, before DNA replication can occur.
Which subunit is present in only one copy per DNA polymerase III?
The DNA polymerase III holoenzyme is a highly asymmetric structure due to the presence of only one copy of each of several subunits (δ, δ′, χ, ψ) in the clamp loader.
What is topoisomerase in DNA replication?
The topoisomerases act by transiently cutting one or both strands of the DNA . Topoisomerase type I cuts one strand whereas topoisomerase type II cuts both strands of the DNA to relax the coil and extend the DNA molecule.
How would a nonfunctional clamp loader affect DNA replication?
It does not break any bonds. Which result would be a consequence of having a nonfunctioning clamp loader in a DNA replication reaction? The polymerase would bind to the wrong area of the DNA. Primers would not be formed .
Which of these is not required for DNA replication?
Explanation: RNA polymerase is an enzyme that transcribes RNA from DNA; it is not essential for DNA replication. This enzyme is easy to confuse with primase, whose primary function is to synthesize the RNA primers necessary for replication.
How does the β clamp processivity factor achieve its role during DNA replication?
β-clamp is loaded on the DNA, by clamp loader, a subunit of DNA Pol III. It interacts with several proteins other than DNA polymerase III subunits; it also freely slides along DNA and improves the processivity of other proteins .
Which is the lagging strand?
The lagging strand is a single DNA strand that, during DNA replication , is replicated in the 5′ – 3′ direction (opposite direction to the replication fork). DNA is added to the lagging strand in discontinuous chunks called ‘okazaki fragments’.
What is the role of RNA Primase?
Primase is an enzyme that synthesizes short RNA sequences called primers . ... Since primase produces RNA molecules, the enzyme is a type of RNA polymerase. Primase functions by synthesizing short RNA sequences that are complementary to a single-stranded piece of DNA, which serves as its template.
What is the role of DNA polymerase III?
DNA Polymerase III, Bacterial
The main function of the third polymerase, Pol III, is duplication of the chromosomal DNA , while other DNA polymerases are involved mostly in DNA repair and translesion DNA synthesis.
