Term
| Proofreading (of DNA polymerase) |
|
Definition
a 3' to 5' exonuclease activity of DNA polymerase that
removes erroneously introduced bases. |
|
|
Term
|
Definition
DNA repair system that recognizes and corrects mismatches in newly
replicated DNA. It recognizes and repairs apposed bases that do not pair properly. It uses an
excision repair method of base removal, but is usually considered separately. |
|
|
Term
|
Definition
| directly reverses DNA damage. |
|
|
Term
|
Definition
replaces DNA damage. The two main types of excision repair are base
excision repair and nucleotide excision repair. Excision repair consists of 4 distinct steps:
incision, excision, resynthesis, and ligation |
|
|
Term
|
Definition
Frist step of Excision repair; refers to the recognition step in excision repair, and is specific for a given type
of damage. |
|
|
Term
|
Definition
| Second step of excision repair; removal of damaged DNA. |
|
|
Term
|
Definition
| 3rd step of excision repair; gap filling by DNA polymerase I |
|
|
Term
|
Definition
| Last step of excision repair; joining of the gap-interrupted stretch of DNA by DNA ligase. |
|
|
Term
| Apurinic-apyyrimidinic (AP) endonuclease |
|
Definition
- recognizes sugar-phosphate resudues that are left over from nucleotides that have lost their purine or pyrimidine bases. Associated with the
incision step of excision repair. |
|
|
Term
|
Definition
- removes modified bases. These enzymes are specific (and specifically
named) for the different types of damage. Associated with the incision step of repair. |
|
|
Term
|
Definition
- emergency response to severe DNA damage in E. coli. It involves the activation
of many genes whose protein products act in this repair. In this repair, blocked replication is
reinstated by skipping over the blocking base residue. Overall, SOS repair is a very inaccurate
repair process, but may be advantageous for long term survival in that it increases genetic
diversity in survivors. |
|
|
