week 3: hemoglobin, protein puification, carbs, and lipids

Question 1

what are ligands

Answer 1

small molecules which bind to proteins

Question 2

what method to ligands bind to proteins

Answer 2

noncovalently

Question 3

describe ligand binding

Answer 3

induces molecular rearrangements, highly conserved and complementary in size, shape, and charge

Question 4

how to quantify ligand binding

Answer 4

degree of saturation

Question 5

how to calulate degree of saturation

Answer 5

theta = [PL] / ([PL] + [P])

Question 6

calculate theta using dissociation constant (Kd)

Answer 6

theta = [L] / (Kd + [L])

Question 7

what does Kd correspond to in terms of ligand binding

Answer 7

concentration of ligand in which 50% of binding sites are occupied

Question 8

what is Mb

Answer 8

small protein in muscles which facilitates O2 diffusion in muscles (O2 storage in aquatic animals) with 1 heme

Question 9

how does Mb facilitate diffusion throughout muscles

Answer 9

binds at high pO2 and releases at very low pO2

Question 10

calculate theta based on P50

Answer 10

theta = pO2 / (p50 + pO2)

Question 11

what is p50

Answer 11

Kd

Question 12

what does Hb do

Answer 12

transports O2 from lungs to peripheral tissues

Question 13

what is the globin fold

Answer 13

8 helices with loops in between

Question 14

what do the differences in Mb and Hb mean

Answer 14

higher p50 of Hb means higher concentration of O2 to bind than Mb

Question 15

why does Hb have a higher p50 than Mb

Answer 15

lower affinity makes it a better transport moelcule – can bind and release while Mb is rarely unbound