11.3 ATP Synthase

Question 1

what are the 3 functional units of ATP synthase?

Answer 1

1. rotor
2. catalytic headpiece
3. stator

Question 2

what are the 4 subunits of the rotor of ATP synthase?

Answer 2

gamma, delta, epsilon, and c ring

Question 3

what is the function of the rotor of ATP synthase?

Answer 3

rotates in response to proton flow

Question 4

what is the function of the catalytic headpiece of ATP synthase?

Answer 4

ATP synthesis

Question 5

what are the 2 functions of the stator of ATP synthase?

Answer 5

1. allow proton flow (enter and exit the c ring)
2. stabilizes ATP synthase in the membrane (helps in STAYtor)

Question 6

what does the F1 component of ATP synthase contain?

Answer 6

3 alpha and 3 beta subunits and one gamma subunit

Question 7

what is the function of the F1 component of ATP synthase? (2)

Answer 7

1. bind ADP and Pi
2. release ATP

Question 8

which part of the F1 component of ATP synthase is catalytic?

Answer 8

only the beta subunits

Question 9

does the F1 component of ATP synthase rotate?

Answer 9

nope

Question 10

what is the function of the gamma subunit of ATP synthase? (2)

Answer 10

1. rotates with the c ring of rotor
2. causes beta subunits to change conformation

Question 11

what is the stator of ATP synthase?

Answer 11

a stationary, membrane bound portion of F1 and F0 made up of a, b, d, h, and OSCP subunits

Question 12

what part of the stator allows protons to enter and exit the c ring? describe

Answer 12

the a subunit, which attaches F1 to F0 and has 2 half channels that let on H+ into the p side while allowing one H+ to exit to the H+ side

Question 13

what is the catalytic portion of F1?

Answer 13

the catalytic headpiece of ATP synthase

Question 14

what are the 3 states that the beta subunits of the catalytic triad can exist in?

Answer 14

O= open: nothing bound
L= loose: ADP and Pi bound
T= tight: ATP bound

Question 15

what does one full rotation of the rotor of ATP synthase yield?

Answer 15

3 ATP

Question 16

how does the rotor of ATP synthase rotate?

Answer 16

counterclockwise from amtrix side

Question 17

what happens with every 120 degree rotation of the rotor of ATP synthase?

Answer 17

3 H+ move from the p side through the F0 component and into the N side

Question 18

what is the F0 component of ATP synthase composed of? (2)

Answer 18

one alpha subunit and one c ring

Question 19

describe the alpha subunit of the F0 component of ATP synthase (2)

Answer 19

1. 2 proton half channels
2. embedded in the membrane

Question 20

describe the c ring of the F0 component of ATP synthase (3)

Answer 20

1. rotates with proton flow
2. made of 10 helices
3. binds H+ with Asp 59

Question 21

describe the concept of the two proton half channel model of the alpha subunit of ATP synthase (2)

Answer 21

1. neither channel fully transverses the membrane
2. protons move from p side through the c ring where the interact with Asp 59 and leave to the N side

Question 22

describe the mechanism of the two proton half-channel model of the alpha subunit of ATP synthase (4)

Answer 22

1. H+ (p side) enters through H+ (p side) half channel
2. H+ (from p side) protonates negative Asp 59
3. this cuases a 36 degree rotation of the c ring
4. protonated Asp 59 releases H+ to N-side through the H+(N side) half channel