Exam 2 Flashcards
Cross-linking agents:
Nitrogen mustard
Cisplatin
Mitomycin C
Carmustine
Alkylating agents
Dimethyl sulfate (DMS) Methyl methanesulfonate (MMS)
Intercalating agent
Thalidomide
UV radiation causes
Pyrimidine dimers
Ionizing radiation causes…
Strand breaks
Chemical mods of bases
DNA protein crosslinks
Non-ionizing radiation causes…
Thymine dimers
Spontaneous DNA damage causes…
Depurination
Deamination
Nucleotide excision repair
- what type of damage does it fix?
- enzymes involved?
- associated disorder?
- fixes chemical addicted that distort DNA (pyrimidine dimers, BPDE-guanine adducts, cisplatin adducts)
- enzymes are NER protein complex, DNA poly, DNA ligase
- xeroderma pigmentosum
Mismatch excision repair
- damage type?
- enzymes?
- disease associated?
- mismatched base in daughter strand
- MER complex, helicase/endonuclease, DNA poly, DNA ligase
- hereditary nonpolyposis colorectal cancers
Homologous recombination associated disorder
BRCA1/2 breast cancer
Transcription coupled repair associated disorder
Cockayne syndrome (also associated with nucleotide excision repair)
Cockayne’s syndrome
Defect in transcription coupled repair
Growth retardation, skeletal abnormalities, sensitivity to sunlight
RNA polymerase is permanently stalled at sites of damage in important genes
Modifications on Lysine residues
Ubiquitination
SUMOylation
Acetylation
Methylation
Modifications on Serine or threonine
Phosphorylation
Duchenne Muscular dystrophy DNA mutation type
Frameshift
Sickle cell anemia DNA mutation type
Missense
Streptomycin
Binds to the 30S subunit to disrupt initiation of translation; interferes with binding fmet-tRNA, blocks association of 30S with 50S
Shiga toxin
Ricin
Binds to the 60S subunit to disrupt elongation by blocking entry of aminoacyl-tRNA to ribosomal complex
Clindamycin
Binds to the 50S subunit to disrupt translocation of the ribosome
Erythromycin
Binds to the 50S subunit to disrupt translocation of the ribosome; commonly used o treat pertussis
Tetracyclines
Bind to the 30S subunit to disrupt elongation by blocking entry of aminoacyl-tRNA to ribosomal complex
Peptidyl transferase activity is housed where?
Large subunits of ribosomes
Diphtheria toxin
Inactivates eEF2-GTP and inhibits elongation, interferes with ribosomal translocation
Chloramphenicol
Inhibits peptidyl transferase (prok./mitoc.)
