CBG08 Flashcards
What is the error rate of DNAP split up?
1/10^5 is DNAP
1/10^2 is its exonuclease
1/10^2 is strand mismatch repair
three types of lesion that coould occur in DNA
c->U via free radicals in oxidative deamination
A-> hole, via depurination by spontaneous hydrolysis
2T-> cytobutane dimer by thymine dimerisation with UV
What effect does bromouracil have?
base analogue of uracil - subs T induce mutation
describe transient base tautomery?
enol/keto
enol-> G keto->A
enol-> creates a UG mutation which you can spot
cg mutation in next replication is permenant
small lesions are fixed via
base exicion
glycosylase (recognises), endonuclease, polymerase, ligase.
large lesions are fixed via
nucleotide excision
describe nucleotide excision
UV repair proteins (including UV induced thymidine dimers) 2UVrA plus 1UVrB trimer scan for damage UVrB remains at site UVrC binds and cuts several bases from damage UVrD helicase binds and seperates DNAP Ligase
what does streptomycines cause?
pyrimidines to be misread
CTU
(smaller)
what does mypirocin cause?
inhibits isoleucyl tRNA synthetase in MRSA infection
what does tmRNA do?
in prokaryotes recognises stalled ribosome binds and recylces proteolysis tag to unfinished PP facilitates mRNA degradation tmRNA = mRNA like domain
Which amino acids are often confused
isoleucine and valine
aspartate and glutamate
serine and threonine
lecuine valine isolecuine and threonine
What is aaRS?
aminoacetyl tRNA synthase
has proof reading esterase
10^-2/aa -> 10^-4/aa
What happens if there is a DS break?
ds break repair
homologous recombination
ss invades homologous duplex at homology region
form displacement loop
3’ end of invading strand acts as DNAP primer
synthesizes and bubble dissociates when done.
