L10 Bacterial ATP synthase Flashcards
how much ATP is consumed in a regular day
65kgs
how much ATP is in the body at any one time
100g
how much O2 is used to produced 65kg of ATP
380L
who discovered F1-F0 ATP synthase
Efraim Racker
what are the fractions of ATP synthase
F1: soluble fraction (hydrolytic activity)
F0: sensitive to oligomycin
how the are the ATP synthase fractions connected
prereferral stalk
where is the F1 fraction found
cytoplasm
where is the f2 fraction found
membrane bound
what happens during ATP synthesis
proton enters a single half channel in the a subunit and docks to the c subunit.
- proton goes around the c subunit and out through the other half channel of the a subunit into the cytoplasm
- as the c subunit rotates with protons it drives the change in conformation of the alpha and beta subunits
What is the functions of ATP synthase
synthesise ATP
hydrolyse ATP
what does the F1 motor consist of
3 alpha subunits + 3 beta subunits = catalytic head
how is the F1 motor connected to the prereferral stalk
delta subunit
what does the prereferral stalk consist of
delta subunit
1 a subunit
2 b subunits
how many c subunits are in the rotor component in mitochondria
8
how many c subunits are in the rotor component in bacteria
9-15
what is the gamma subunit
central stalk that
where is the epsilon subunit found
connected to the gamma subunits
what does the rotary element of ATP synthase consist of
c-subunits
gamma subunit
epsilon subunit
describe the A subunit of ATP synthase
extremely hydrophobic with hydrophilic channels
how many revolutions per second does the c subunit do
134
how many molecules of ATP are produced in one rotation of the C subunit
3
what subunits is ATP synthesised on
beta
when the conc of the proton motive force gets low what can bacteria do
hydrolyse ATP
what happens when ATP is hydrolyses
c subunit rotates in opposite direction and protons move from the cytoplasm to the outside of the cell
which motor is responsible for synthesis and which is for hydrolysis
F1: hydrolysis
FO: synthesis
what were the three conformations of the beta subunits
beta e: empty
beta dp: ADP bound
beta tp: ATP bound
where does the gamma subunit sit
in the middle of the catalytic head, connected to the beta subunits
what happens when the gamma subunit rotates
the beta subunits change conformation
how was the rotational hypothesis proven
tethered ATP synthase upside to glass and attached the gamma subunit to a fluorescent actin filament rather than the c subunit.
looked at hydrolysis of ATP to ADP
how does ATP synthase rotate
120 degrees then pause
x 3
within 120 degrees, there were 90 degree (ATP binding) and 30-degree rotation (ADP release)
