DNA replication #1 Flashcards
Indicator protein
opens up double helix and recruits helicases
ssDNA binding proteins
protect ssDNA
Bacteria = SSB
Eukaryotic = RPA
Helicase polarity
the direction moved on the strand that is bound
DNA gyrase (II)
introduces negative supercoils
What three things does DNA synthesis require?
~ dNTPs
~ primer:template junction
~ DNA polymerase
dNTP means…
Deoxynucleotide triphosphate
Processive synthesis
replicative polymerase stay attached for many 1000s of nucleotides
Distributive synthesis
some DNA pols only add a few nucleotides before falling off
PCNA
proliferating cell nuclear antigen
~ common in proliferating cells
~ eukaryotic
~ ring structure made up of 3 polypeptide each with two domains
Origin
the ability to bind initiator proteins
ORC
Origin recognition complex
~ binds to eukaryotic origins
~ indicator protein
Primer
a short piece of RNA or DNA+RNA and is synthesised by DNA primase (a type of RNA polymerase)
Which direction does bacterial DNA helicase work?
5’ –> 3’ on lagging strand
Which direction does eukaryotic DNA helicase work?
3’ –> 5’ leading strand
What is the core of eukaryotic DNA helicase?
Mini chromosome maintains (MCM)
What is the bacterial DNA helicase?
DnaB
~ lodged onto DNA by DnaC
Which DNA pols for bacetria/eukaryotes use?
Bacteria = DNA pol III Eukaryotes = DNA pol II, delta and epsilon
Topoisomerase
releases supercoiled DNA by breaking it, allowing the supercoils to relax and rejoining it
