LIFESCI 3 Lecture 3: protein
Document Summary
Griffith experiment: rough vs smooth bacteria (smooth ones have capsules, smooth: virulent; rough: nonvirulent, combine extract of heat-killed virulent with live nonvirulent bactiera, some live bacteria. Dnases - degrade dna into individual subunits. Rnases - degrade rna into individual subunits. Dnase destroys ability of heated extract to transform r strain into lethal smooth (s) strain. Dna or proteins carries genetic information: griffith, avery, hershey chase experiment. Bacteriophage (protein shell + dna genome) -> transform bacteria into phage machine. Take phage, some label dna, some label protein shell. Peptides usually contain less than 20-30 amino acids. Proteins usually contain 100 or more aa: polarity/directionality. Whe(cid:374) joi(cid:374)i(cid:374)g: n to c; a(cid:374)alogous to (cid:862)5" to 3"(cid:863) for (cid:374)u(cid:272)lei(cid:272) a(cid:272)id interactions. R group interactions -> weak/strong association of proteins. Strong/weak association depends on favorability of r group on the surface of the protein. Non-covalent bonds are critical for interactions between macromolecules thru condensation reaction: peptide bonds resonant, and are planar, polar charged aa.
