ALLOSTERIC EFFECTS QUIZ

2

None of these

not defined

1

it is displaced from the heme by movement of the proximal histidine

BPG binds to the R state with the same affinity as the T state

its binding pocket becomes too small to accommodate BPG

it is displaced from the heme by oxygen

binding of oxygen to the heme

reorganization of protein-protein contacts between the individual subunits

movement of the F-helix, which contains the proximal His

movement of the proximal histidine towards the heme

both (b) and (c)

only be found in either the unliganded form or the fully liganded form

show a Hill coefficient (nH) of 0.0

show a Hill coefficient (nH) of n

1.0 and 2.8

2.8 and 1.0

1.2 and 4.5

4.5 and 1.2

the opposite chirality of the binding ligand

the absence of competing ligands

the amino acid residues lining the binding site

the presence of hydrating water molecules

both (a) and (c)

stabilizes the R state of the protein

increases the binding affinity

decreases the binding affinity

decreasing Hb affinity for O2

increasing [H+]

increasing [H+] and decreasing Hb affinity for O2

increasing Hb affinity for O2

extensive protein conformational change

100-fold lower affinity for the last O2 bound than for the first

100-fold higher affinity for the last O2 bound than for the first

both (a) and (b)

for maintaining Fe in the Fe2+ state

to minimize oxygen delivery to the tissues

only in humans

to maximize oxygen delivery to the tissues