4.4 Denaturation, Folding and summary

Question 1

what does refolding of disuphide bonds and denaturation say about proteins

Answer 1

dramatic demonstration of rlnshp btwn primary structure and forces that determine tertiary stucture

Question 2

how does heat denature

Answer 2

increase temp favours vibrations w/in molecule. nrg of vibration great enough to disrupt tertiary structure

Question 3

high can high or low extremes of pH denature

Answer 3

some charges on proteins are missing, so electostatic interaxn that would staballize native active form are drastically reduced

Question 4

how can binding of detergents denature

Answer 4

SDS disrupt hydrophbic interaxns. if detergent charged, disrupts electrostatic interaxn w/in protein

Question 5

how can urea and guadinine hydrochloride denature proteins

Answer 5

form H2 bonds w/protein that are stronger than those w/in protein itself. also disrupt hydrophobic interaxm similar to detergents

Question 6

beta mercaptoethanol is used to

Answer 6

reduce disulphide bridges to sulphydryl groups,urea added to rxn mixture to facilitate unfolding of protein and increase accessibility of disulfide to reducing agent

Question 7

how can native confromation of protein be recovered if reagents were used

Answer 7

maercaptoethanol and urea removed

Question 8

what is the tertiary structure

Answer 8

complete 3-d arrangement of all atoms in a protein

Question 9

where does H2 bonding occur

Answer 9

btwn atoms on peptide backbone as as well as atoms in side chains

Question 10

how can tertiary structure be determined

Answer 10

x-ray crystallography and NMR