Molecular biology Flashcards
Daunorubicin and doxorubicin
Antitumor drugs that intercalate between bases of DNA to interfere with the activity of topoisomerases and prevent proper replication of the DNA .
Treat leukemias.
Cisplatin
Antitumor drug that binds tightly to DNA, causing structural distortion and malfunction.
Treat bladder and lung tumors.
p53 gene
Encodes protein that prevents cell with damaged DNA from entering S phase
Inactivation/deletion associated with Li Fraumeni syndrome and many solid tumors
ATM gene
Encodes kinase essential for p53 activity
Inactivated in ataxia telangiectasia (hypersensitiity to x-rays and predisposition to lymphomas)
Rb gene
Encodes protein that binds transcription factor E2F and represses transcription of genes required for S phase.
Shiga toxin and Shiga-like toxins
Inhibit protein synthesis in eukaryotic cells by clipping an adenine residue from the 28S rRNA in the 60s subunit
Pseudomonas and Diptheria toxins
Inhibit the transloctation step of the translation process in eukaryotic cells via ADP-ribosylation of elongation factor-2 (eEF-2)
Gray baby syndrome
Potentially deadly reaction that occurs in newborns (especially premies) who are given chloramphenicol (inhibits mitochondrial protein synthesis)
Infants do not have sufficient UDP-glucuronyl transferase activity needed to allow excretion of chloramphenicol
Cyanosis, hypotension, death.
Post-translational modification of collagen
- Synthesis of prepro-alpha chains with hydrophobic signal sequence by RER ribosomes
- Removal of signal sequence by signal peptidase in the RER to produce pro-alpha chain
- Hydroxylation of selected prolines and lysines in the RER (requires Vit C)
- Glycosylation of selected hydroxylysines
- Triple helix forms and is further modified in the Golgi before secretion as procollagen
- Cleavage of propeptides to form tropocollagen
- Collagen assembles into fibrils; stabilized by lysyl oxidase (requires Cu, deficient in Menkes disease)
- Fibrils aggregate and cross-link to form collagen fibers
