BIOL 202 Lecture Notes - Lecture 12: Ames Test, Sulfonate, Dna Ligase
Document Summary
Changes in protein amino acid sequence can lead to: no effect on protein function, loss-of-function. Weak/partial: protein retains some function or only some protein is made (hypomorphic) Protein is non-functional or is not made (null: gain-of-function. More protein is made or made in wrong time/place (ectopic) Mutagens and induced mutagens chemicals that cause dna damage or alteration. Can act through the following mechanisms: base replacement. Can adopt less stable configurations, shifting affinities and leading to nt change. 5-bromouracil- analog of t: can cause a-t g-c or vice versa. 2-aminopurine- analog of a: can mispair with c, leading to transitions, base alteration (mispairing) i. e. alkylating agents such as ems (ethylmethan sulfonate) or nitrosoguanidine (ng) which add ethyl and methyl groups respectively. Alkylation of o-6 position of g changes basepairing specificity: causes g-c a-t transitions frequently introduces stop codons, base damage (prevents base pairing) i. e. uv radiation. Causes adjacent pyrimidines to interact with each other and form unusual covalent bonds.
